Does it ever happen after the page refreshes or anything of the sort? Or after your internet 'suddenly shuts off'? ouo.
If no~ I'd suggest just re-freshing the page and all every so often, even if you are 8rowsing a8out quite a8it~ That's what I once did to prevent these issues, annoying though, I know -Flail-
Another thing I did after this started was type a random, large num8er in that space instead of checking 'Log in forever'- ouo. Even though it sort of just turns 8ack into 'Log-in forever'~
Cause' after I did that-- well, I haven't had to type my password for three months ouo.