[OpenAFS] Losing tokens

[Jeff Blaine]

We have users here and there reporting that they are mysteriously
losing their tokens sometimes (quite rare).  We've worked with
them to the point where they are able to produce terminal
session captures that show initial tokens from login that then
disappear eventually (before expiration time).

So far we've only been able to associate the problem with
OpenAFS 1.4.11 for RHELv5.

I'm looking for advice as for how to start debugging this.