My WD Mycloud EX2 Ultra is copying always

Hey there

I have got a WD Mycloud EX2 Ultra with 2 drives in RAID1 mode. Since 2 weeks I hear that the device is working a lot. 24/7 noise like its copying data much data but in fact I didnt moved much data which the device has to copy. All diagnostics in OS are green, no errors found, I restarted the device 3-4 times without any change, both drives are „OK“, complete system disgnostics made without problems. Sometimes error 2020 comes (system shutdown), I dont know why…

If someone can help me, would be very much appriciated.