You may be running into a visual bug - when you go to log in, there is sometimes a space at the beginning of either the username or password entry box, though it's hard to see if that is the case. Could you check that the username and password do not have a space at the beginning? I cannot reproduce the issue here on any of the architectures we support with a live image.

no, there were no spaces. I tried both "lock" and full logoff, and entered login and pass from zero..
but at that moment that I was shoot a video, i was able to successfully login.
rebooted 4 times, and the bug didn’t appear anymore .. I don’t understand what it’s connected with ..

I rebooted for 2020.2 4 times, only for today, and +5 more times before downloading the update. after updated to 2020.4 and rebooted for another twice, but the bug remained ..
but now it's gone .. I don’t know how it works. maybe vram ..

but in 2020.2 it was for sure, since repeated many times.
I hope it doesn't come back again soon at the worst moment ...

This report has been filed against an old version of Kali. We will be closing this ticket due to inactivity.

Please could you see if you are able to replicate this issue with the latest version of Kali Linux (https://www.kali.org/get-kali/)?

If you are still facing the same problem, feel free to re-open the ticket. If you choose to do this, could you provide more information to the issue you are facing, and also give information about your setup?
For more information, please read: https://www.kali.org/docs/community/submitting-issues-kali-bug-tracker/