Any hints or tips on how to debug an elusive timer error?

[Live System User]

Hi,

   Does anybody have any hints or tips on how to debug
   an elusive timer error?

   I seem to periodically getting the error:

Error running timer ‘show-paren-function’: (wrong-type-argument stringp
t) [2 times]

   Although it is not readily reproducible I seem to notice
   it more when doing a "M-:" `eval-expression'.

   This is while not yet typing RET when pausing and/or continuing
   to type the elisp expression.
   
   Thanks.