A long time LP user experiencing a first problem today. One of numerous vault sites which always worked perfectly would suddenly return the 'invalid username or password' message. Entering the exact same data manually would work successfully. Since it was my ISP's site I was attempting to access, I contacted their support who suggested a probable Chrome issue and since it continued to misbehave even after clearing all history, cache, cookies, etc., they suggested removing and re-installing Chrome which I did.
The same issue continued afterwards so questioning the vault entry, I decided to delete it and simply reenter it exactly as it always was after which it worked perfectly. So my question is, can entries go bad even though they worked perfectly for years and no changes were ever made? Suggested causes?