Keyboard processing fails intermittently

From time to time entering characters from the keyboard does not operate correctly. Characters are dropped or ignored; when this is occuring, it is impossible to enter a correct password.

I have not isolated the problem to any particular application.

It occurs on average about once a month, so it's nothing I'm going to throw myself on my sword about, but it has prevented me from logging in at times.

It occurs most often in short character fields, such as for a password.

It has survived several upgrades.

I am operating an HP personal computer.

Keyboard processing is done mostly in the BIOS, so I'm surprised to see it occurring in TriSquel (it doesn't happen in Windows). I have not found it in other distributions of GNU/Linux.

This is pretty arcane and will be difficult to isolate. I will report any further occurences.

Paul