Yep, big problem with them: most users have no idea where the thing that pops up and offers to store the passkeys actually stores them (sounds like in your case, in your computer's TPM was either on the CPU you replaced or complained and reset itself when the CPU changed). It's a ticking timebomb that all the 'users love passkeys! (after we nag them about it every time they login until they give up)' blogs fail to catch.