15" tbMBP BigSur booting to Disk Password

[jabz10]

Hi I just booted my tbMBP which has BigSur and it keeps booting to a Disk Password user login screen,
No users are shown on the login screen I have 2 user accounts. Normally all 3 are shown on the login screen.

It was working perfectly fine a few days ago, and has 2 accounts on it. I don't remember the disk encryption password, (there wasn't really any need for me to encrypt and probably just chose it during setup to get it running few years ago)

Is there a way to get in now? Why would it suddenly just boot to a disk password user login screen?

EDIT: I just booted into recovery mode, and it to boots to a "Select a user you know the password for:" and only shows the Disk Password user. What happened to my other 2 accounts, and why aren't they showing?

 

[jabz10]

update, in recovery mode, I chose forgot passwords for all accounts (I haven't, but that's the only other choice)
It promoted me to login to my Apple ID (2FA) and after that showed me my user accounts, I picked one to reset the password for. Then restarted and its back to normal. WTH.

Currently its decrypting, since I disabled file vault.