locked I did not know that! Thanks for the information!
It seems to happen on several devices, (In my case both the Pixel 6a, 7 and Tablet) but for me personally it isn't a big deal, I just lock, unlock and type the password. (You don't have to type it first before the initial locking, so that saves some effort. So just once will do after reopening the lockscreen again)
But indeed, it has been going on for several months, and does not seem related to the most recent updates, if any.