Mux issue

Can anyone tell me why I have this problem?

I monitor my calls, and at the end of the call, they get mux’ed together. If the call is longer than a few minutes (the longer the call, the worse it becomes) the calls end up getting WAY out of sync. By out of sync I mean one person is answering a question that hasn’t been asked yet on the phone call until a few seconds later.

Has anyone ever had this issue before? Any suggestions on what I can try?

I’m running Asterisk 1.4.0

I am recording the calls in WAV format, and this is the monitor line I use:

exten => s,1,Monitor(wav,to-${callto}-from-${callfrom}-${STRFTIME(${EPOCH},EST,%A %m-%d-%Y %I_%M_%S %p)},m)