Connecting external USB 3.0 2-bay dock to MyCloud EX2 - only one drive is mounted

yes it is possible, the second drive is detected by the underlying OS. However i must mount it manually, so it is only a question regarding implementation of the software of the ex2.
There are several threads on this forum with people having the same issue…

for example:

Is this issue already in progress? It seems more to be a bug than a new feature, because External Drives, which are connected via powered usb hub are functioning.
Where can I find the logfiles, to see if mounting or the software throws an error?

Edit: this is the output of the dmesg command. I cleared it before plugging in the USB drive.

[Fri Dec 9 14:36:27 2016] xhci_hcd 0000:00:00.0: Cannot set link state.
[Fri Dec 9 14:36:27 2016] hub 4-0:1.0: cannot disable port 1 (err = -32)
[Fri Dec 9 14:36:27 2016] hub 4-0:1.0: cannot disable port 1 (err = -32)
[Fri Dec 9 14:36:27 2016] usb 4-1: USB disconnect, device number 7
[Fri Dec 9 14:36:27 2016] hotPlug.sh begin(seq=750)…
[Fri Dec 9 14:36:27 2016] hotPlug.sh end(seq=750).
[Fri Dec 9 14:36:27 2016] hotPlug.sh begin(seq=759)…
[Fri Dec 9 14:36:27 2016] hotPlug.sh end(seq=759).
[Fri Dec 9 14:36:27 2016] hub 3-0:1.0: unable to enumerate USB device on port 1
[Fri Dec 9 14:36:27 2016] usb 4-1: new SuperSpeed USB device number 8 using xhci_hcd
[Fri Dec 9 14:36:27 2016] scsi9 : usb-storage 4-1:1.0
[Fri Dec 9 14:36:27 2016] scsi 9:0:0:0: Direct-Access WDC WD64 01AALS-00L3B2 0000 PQ: 0 ANSI: 2 CCS
[Fri Dec 9 14:36:27 2016] sd 9:0:0:0: [sdc] 1250263728 512-byte logical blocks: (640 GB/596 GiB)
[Fri Dec 9 14:36:27 2016] xhci_hcd 0000:00:00.0: WARN: Stalled endpoint
[Fri Dec 9 14:36:27 2016] sd 9:0:0:0: Attached scsi generic sg2 type 0
[Fri Dec 9 14:36:27 2016] sd 9:0:0:0: [sdc] Write Protect is off
[Fri Dec 9 14:36:27 2016] sd 9:0:0:0: [sdc] Mode Sense: 28 00 00 00
[Fri Dec 9 14:36:27 2016] xhci_hcd 0000:00:00.0: WARN: Stalled endpoint
[Fri Dec 9 14:36:27 2016] scsi 9:0:0:1: Direct-Access WDC WD20 EARX-00PASB0 0000 PQ: 0 ANSI: 2 CCS
[Fri Dec 9 14:36:27 2016] sd 9:0:0:0: [sdc] No Caching mode page present
[Fri Dec 9 14:36:27 2016] sd 9:0:0:0: [sdc] Assuming drive cache: write through
[Fri Dec 9 14:36:27 2016] sd 9:0:0:1: [sdd] 3907029168 512-byte logical blocks: (2.00 TB/1.81 TiB)
[Fri Dec 9 14:36:27 2016] xhci_hcd 0000:00:00.0: WARN: Stalled endpoint
[Fri Dec 9 14:36:27 2016] sd 9:0:0:1: Attached scsi generic sg3 type 0
[Fri Dec 9 14:36:27 2016] sd 9:0:0:1: [sdd] Write Protect is off
[Fri Dec 9 14:36:27 2016] sd 9:0:0:1: [sdd] Mode Sense: 28 00 00 00
[Fri Dec 9 14:36:27 2016] xhci_hcd 0000:00:00.0: WARN: Stalled endpoint
[Fri Dec 9 14:36:27 2016] sd 9:0:0:1: [sdd] No Caching mode page present
[Fri Dec 9 14:36:27 2016] sd 9:0:0:1: [sdd] Assuming drive cache: write through
[Fri Dec 9 14:36:27 2016] xhci_hcd 0000:00:00.0: WARN: Stalled endpoint
[Fri Dec 9 14:36:27 2016] xhci_hcd 0000:00:00.0: WARN: Stalled endpoint
[Fri Dec 9 14:36:27 2016] sd 9:0:0:0: [sdc] No Caching mode page present
[Fri Dec 9 14:36:27 2016] sd 9:0:0:0: [sdc] Assuming drive cache: write through
[Fri Dec 9 14:36:27 2016] sdc: unknown partition table
[Fri Dec 9 14:36:27 2016] xhci_hcd 0000:00:00.0: WARN: Stalled endpoint
[Fri Dec 9 14:36:27 2016] xhci_hcd 0000:00:00.0: WARN: Stalled endpoint
[Fri Dec 9 14:36:27 2016] sd 9:0:0:1: [sdd] No Caching mode page present
[Fri Dec 9 14:36:27 2016] sd 9:0:0:1: [sdd] Assuming drive cache: write through
[Fri Dec 9 14:36:27 2016] xhci_hcd 0000:00:00.0: WARN: Stalled endpoint
[Fri Dec 9 14:36:27 2016] xhci_hcd 0000:00:00.0: WARN: Stalled endpoint
[Fri Dec 9 14:36:27 2016] hotPlug.sh begin(seq=785)…
[Fri Dec 9 14:36:27 2016] sd 9:0:0:0: [sdc] No Caching mode page present
[Fri Dec 9 14:36:27 2016] sd 9:0:0:0: [sdc] Assuming drive cache: write through
[Fri Dec 9 14:36:27 2016] sd 9:0:0:0: [sdc] Attached SCSI disk
[Fri Dec 9 14:36:27 2016] sdd: sdd1 sdd2
[Fri Dec 9 14:36:27 2016] xhci_hcd 0000:00:00.0: WARN: Stalled endpoint
[Fri Dec 9 14:36:27 2016] xhci_hcd 0000:00:00.0: WARN: Stalled endpoint
[Fri Dec 9 14:36:27 2016] sd 9:0:0:1: [sdd] No Caching mode page present
[Fri Dec 9 14:36:27 2016] sd 9:0:0:1: [sdd] Assuming drive cache: write through
[Fri Dec 9 14:36:27 2016] sd 9:0:0:1: [sdd] Attached SCSI disk
[Fri Dec 9 14:36:27 2016] hotPlug.sh end(seq=785).
[Fri Dec 9 14:36:27 2016] hotPlug.sh begin(seq=786)…
[Fri Dec 9 14:36:27 2016] hotPlug.sh end(seq=786).
[Fri Dec 9 14:36:27 2016] FAT-fs (sdc): bogus number of reserved sectors
[Fri Dec 9 14:36:27 2016] FAT-fs (sdc): Can’t find a valid FAT filesystem
[Fri Dec 9 14:36:27 2016] ufsd:
[Fri Dec 9 14:36:27 2016] ufsd:======NTFSBoot->le(0)======
[Fri Dec 9 14:36:27 2016] ufsd:Signature : 0x0000000000000000
[Fri Dec 9 14:36:27 2016] ufsd:RWBlocks : 0x4a8582b0 x 0x200, sdc, rw
[Fri Dec 9 14:36:27 2016] ufsd:SectorsPerVolume : 0x0 x 0x0
[Fri Dec 9 14:36:27 2016] ufsd:SectorsPerCluster : 0x0
[Fri Dec 9 14:36:27 2016] ufsd:MFT : 0x0
[Fri Dec 9 14:36:27 2016] ufsd:MFTMirr : 0x0
[Fri Dec 9 14:36:27 2016] ufsd:Record size : 0
[Fri Dec 9 14:36:27 2016] ufsd:Index size : 0
[Fri Dec 9 14:36:27 2016] ufsd:Magic : 0x55aa
[Fri Dec 9 14:36:27 2016] ufsd:===========================
[Fri Dec 9 14:36:27 2016] ufsd:Invalid NTFS boot signature
[Fri Dec 9 14:36:27 2016] ufsd:
[Fri Dec 9 14:36:27 2016] ufsd:=== HfsVolumeHeader->le =========
[Fri Dec 9 14:36:27 2016] ufsd:Signature : (s
[Fri Dec 9 14:36:27 2016] ufsd:Version : 10945
[Fri Dec 9 14:36:27 2016] ufsd:Attributes : 0x1ff8d211
[Fri Dec 9 14:36:27 2016] ufsd:LastMounted : (null)
[Fri Dec 9 14:36:27 2016] ufsd:BytesPerBlock : 0x27400600
[Fri Dec 9 14:36:27 2016] ufsd:Invalid HFS+ signature at 2
[Fri Dec 9 14:36:27 2016] ufsd:Trying to parse gpt at: 1
[Fri Dec 9 14:36:27 2016] ufsd: “mount” (sdc): Trying to parse gpt at: 1
[Fri Dec 9 14:36:27 2016] ufsd:Trying gpt partition : 64028 4a7b4260
[Fri Dec 9 14:36:27 2016] ufsd: “mount” (sdc): Trying gpt partition : 64028 4a7b4260
[Fri Dec 9 14:36:27 2016] ufsd:
[Fri Dec 9 14:36:27 2016] ufsd:=== HfsVolumeHeader->le =========
[Fri Dec 9 14:36:27 2016] ufsd:Signature : H+
[Fri Dec 9 14:36:27 2016] ufsd:Version : 4
[Fri Dec 9 14:36:27 2016] ufsd:Attributes : 0x80002100
[Fri Dec 9 14:36:27 2016] ufsd:LastMounted : HFSJ
[Fri Dec 9 14:36:27 2016] ufsd:BytesPerBlock : 0x1000
[Fri Dec 9 14:36:27 2016] ufsd:RWBlocks : 0x4a8582b0 x 0x200, sdc, rw
[Fri Dec 9 14:36:27 2016] ufsd:TotalSectors : 0x4a7b4260
[Fri Dec 9 14:36:27 2016] ufsd:TotalBlocks : 0x94f684c
[Fri Dec 9 14:36:27 2016] ufsd:FilesCount : 61
[Fri Dec 9 14:36:27 2016] ufsd:FoldersCount : 20
[Fri Dec 9 14:36:27 2016] ufsd:Serial number : b5febaec-df981416
[Fri Dec 9 14:36:27 2016] ufsd:ModifyDate : 0xd4708705
[Fri Dec 9 14:36:27 2016] ufsd:FreeBlocks : 0x94d19ca
[Fri Dec 9 14:36:27 2016] ufsd:NextCatalogId : 0x8c
[Fri Dec 9 14:36:27 2016] ufsd:WriteCount : 0xdb
[Fri Dec 9 14:36:27 2016] ufsd:Allocation : 0x0000129f [0x00000001 + 0x129f)
[Fri Dec 9 14:36:27 2016] ufsd:Extens : 0x00000b00 [0x000042a1 + 0xb00)
[Fri Dec 9 14:36:27 2016] ufsd:Catalog : 0x00010000 [0x000b4da1 + 0x10000)
[Fri Dec 9 14:36:27 2016] ufsd:Attributes : 0x00010000 [0x00004da1 + 0x10000)
[Fri Dec 9 14:36:27 2016] ufsd:EmbeddedOff : 0xc805000
[Fri Dec 9 14:36:27 2016] ufsd:EmbeddedBytes : 0x94f684c000
[Fri Dec 9 14:36:27 2016] ufsd:AltHdrOffset : 0x94f684bc00
[Fri Dec 9 14:36:27 2016] ufsd:===========================
[Fri Dec 9 14:36:27 2016] ufsd:VolumeHeader is accepted as embedded HFS+ 4.0 of size 595.85 Gb
[Fri Dec 9 14:36:27 2016] ufsd:Journal info:
[Fri Dec 9 14:36:27 2016] ufsd: flags: 1
[Fri Dec 9 14:36:27 2016] ufsd: offset: 12a1000 (9508)
[Fri Dec 9 14:36:27 2016] ufsd: size: 3000000 (18000)
[Fri Dec 9 14:36:27 2016] ufsd:Journal header:
[Fri Dec 9 14:36:27 2016] ufsd: magic: 4a4e4c78 (JNLx)
[Fri Dec 9 14:36:27 2016] ufsd: endian: 12345678
[Fri Dec 9 14:36:27 2016] ufsd: start: 1000
[Fri Dec 9 14:36:27 2016] ufsd: end: 1000
[Fri Dec 9 14:36:27 2016] ufsd: size: 3000000
[Fri Dec 9 14:36:27 2016] ufsd: blhdr: 1000
[Fri Dec 9 14:36:27 2016] ufsd: chksum: 88cab4c
[Fri Dec 9 14:36:27 2016] ufsd: jhdr: 1000
[Fri Dec 9 14:36:27 2016] ufsd: seq: fed660,fec3aa
[Fri Dec 9 14:36:27 2016] ufsd:Update hdr
[Fri Dec 9 14:36:27 2016] ufsd:[1000 - 1000) sz=3000000, blhdr=1000, jhdr=1000, 0
[Fri Dec 9 14:36:27 2016] ufsd:jnl_op.load(9ca6fba0, daa6000)
[Fri Dec 9 14:36:27 2016] ufsd:Journal is activated
[Fri Dec 9 14:36:27 2016] ufsd:ExtTree nodes: total b00, free aff, size 1000
[Fri Dec 9 14:36:27 2016] ufsd:CatTree nodes: total 8000, free 7ff8, size 2000
[Fri Dec 9 14:36:27 2016] ufsd:Detected case-insensitive catalog
[Fri Dec 9 14:36:27 2016] ufsd:AttTree nodes: total 8000, free 7ffe, size 2000
[Fri Dec 9 14:36:27 2016] ufsd:Loading Bitmap…
[Fri Dec 9 14:36:27 2016] ufsd:Bitmap: Bits 94f684c, frames 129f x 1000, free 94d19ca
[Fri Dec 9 14:36:27 2016] ufsd:Zone: [198006,1b8006) - 20000 clusters
[Fri Dec 9 14:36:27 2016] ufsd:sizeof(CFileSystemHfs) = 3888
[Fri Dec 9 14:36:27 2016] ufsd: “mount” (sdc): force nocase=1
[Fri Dec 9 14:36:27 2016] ufsd:Label : TimeMachine2
[Fri Dec 9 14:36:27 2016] ufsd:FileLinkFolderId 12, DirLinkFolderId 13
[Fri Dec 9 14:36:27 2016] ufsd: “mount” (sdc): is mounted as HFSJ (journal started)
[Fri Dec 9 14:36:27 2016] ufsd:ioctl:OnGetVolumeInfo
[Fri Dec 9 14:36:27 2016] ufsd:GetVolumeInfo: Free = 0, State = clean

Both drives are formatted properly and i can access them both on my macbook. They are mounted on the WDMycloud when only 1 drive is inserted in the dock, regardless which slot.
AS i already said, i can mount the second drive manually but then it isn’t recognized as share…