raid5 degraded after reboot every time!

I change one bed disk for my ex4 raid5

and it show degrade every time when reboot, and will not auto rebuild

I try use command “mdadm -add /dev/md1 /dev/sdd2” to fix this probleam

then raid rebuild finish,

but when I shutdown and reboot, EX4, it became degrade again!

NOTICE: shutdown and reboot, if reboot directly, it wil be fine, but shutdown and reboot, it will degrade!

I search from on web, It shows a bug in mdadm, but already fixed in new version, doe’s WD EX4 use the version have bug?

The article url:

today, I delete my volumn, and rebuild whole disk to raid5

but when I shutdown and reboot

It shows raid degrade again!

Can you just  fix this stupid problem ?  EX4 can do nothing but wast my time!!!