logfetch unreliable?

I am in the throws of replacing a commercial monitoring product with xymon.  (Before this product we ran  big brother. )

But I am in a pickle.  The commercial product picked up a log entry last night, that xymon did not. I know this because both products are alerting currently.    My biggest issue is the non-report is not reproducible. If I send test messages into my fake log, it works - but I have proof it failed last night in the real log file. How do I even go about debugging this? 

My client-local.cfg  has 

[nemo]
log:/var/log/fake.log:1024
trigger "Notify Mainframe On-Call."
log:/var/log/rmsupload.log:1024
trigger "Notify Mainframe On-Call."


G