Cannot create users which starts with numbers after firmware upgrade

So after an upgrade to the latest firmware for the EX4, we cannot create users that starts with numbers.

The error is:
The user must be an alphanumeric value from 1 to 16 characters, and the first character must be a letter.

See screenshot here:

Any ideas on how to resolve this? If not, is there any way to downgrade the firmware version?

Please note this subforum is for the single drive My Cloud units. You will probably have better luck in the EX4 subforum:
https://community.wd.com/c/network-attached-storage/wd-my-cloud-ex4

Oh, sorry. Didn’t see the subforum. Thank you.

Hello,

The thread has been moved to the correct forum.