Copter-4.5.1 released!

I have 3 out of 12 Pixhawk V6Xs got IOMCU error after upgraded from 4.2.3(factory version)/4.4.4 to 4.5.0/4.5.1.

The relative error messages:
IOMCU: 0 0 0
Config Error: Failed to update IO firmware
Config Error: fix problem then reboot

I’ve tried holding the safety switch while plugging the usb cable. Then it showed:
IOMCU: 0 0 0
PreArm: IOMCU is unhealthy

After that I reboot the FC normally, it showed the same error messages again:
IOMCU: 0 0 0
Config Error: Failed to update IO firmware
Config Error: fix problem then reboot

Could that be due to a bug or just hardware issues?