MyCloudEX2Ultra Too long migration to RAID 1

Firmware 2.31.149

Why its too long?
Can i stop this proccess to copy some files and change raid mode without migration?

I’m in the midst of a similar issue, migrating from JBOD to RAID 5. It has been stuck on 5% and 3719 minutes remaining for 10 hours. The PR4100 went into standby mode overnight after starting the migration and I can’t do anything about it.