My CMF Phone 2 Pro automatically locked itself

I was using my phone normally, then I went to my room and came back after 2 minutes, tried to unlock my phone using fingerprint, as I usually do.

It was not showing the fingerprint unlock and saying to put the letter password, but I had set a 4 digit PIn password. I was shocked bcoz I didn't changed my password.

I put may pin password by using the numbers in the letter keyboard but it was clearly asking for a letter password not a pin one. Then I put my Google account password hoping that this might be a glitch.The phone didn't unlock, instead it said that I only have 2 more attempts to unlock my phone or my work app data will be deleted.

I had some apps that is used for my office, usual apps used for office work.

I was shocked what to do now, i tried to put my work profile password that the company gave me to access my work profile in the apps, but it again said wrong password.

Mind you I didn't change my PIN code, it was the same 4 digit pin I used to unlock my phone.

I then restarted my phone I hope that this issue will go away, but it didn't. I rebooted my phone using the force reboot done by using volume keys, but it was again not taking my original pin code and was saying wrong pin.

I went to the service centre, the said the saw this issue for the first time in there life, and said that they'll just factory data reset my phone. They were useless ffs.

I came back and factory data reset my phone myself, installed everything again, but the phone was saying that the previous data has been saved on my device locally and can only be unlocked by entering the password.

But i didn't know what the LETTER password was, I just put all my guesses and hoped that my phone data will return back, but nothing worked.

I gave up, I just setup my phone again by installing all the apps, hopefully I had turned backup for all the apps i wanted.

It was really wierd experience. Has anyone got the same problem?

Like how the phone locked itself and was demanding a Letter password when I only had a 4 digit password, and didn't take any password related to my work profile or work apps, like actual what the f**k was this sh*t about?