Thank you so much for this post. I had this exact same issue on UNRAID 6.12.10
For me, the script wouldn't run, seemingly because the names in /dev/ had changes so I manually ran dd and cleared things out. Then I couldn't stop the array but I followed your steps and everything seems to be working perfectly now.
**EDIT**
Whoops, I wasn't using "clear_array_for_shrink", I was trying to use "clear_an_array_drive" but had the same symptoms