Lost procs

Look at the clientlog column for that client.  Do you see anything under
"[ps]"?

Should have mentioned, yes. The "[ps]" section of clientlog is fully populated.

Is there anything interesting in the xymon logs on the client (usually, but
not always, in ~xymon/client/logs).

I hadn't checked the client logs, good idea! Nothing interesting there, just logfetch barking when the syslog/messages file gets rotated.

Thanks for your thoughts!

--Chris--