For example, say at a particular moment, the existing mail file looks like:
Message 1 + Message 2 + Message 3 + Message 4
Formail processes this as
Message 1
Message 2 + Message 3
Message 4
We had a similar problem crop up recently. I didn't notice anything
unusual in the mail stream. Whether it's coincidence or not, I had just
upgraded to 3.11pre3 from 2.92pre11. My solution may well not be
applicable in your situation. I used the opportunity to switch to using
procmail as the local delivery agent (as opposed to having smail handle
it directly) and telling popclient to hand mail off to procmail instead
of postprocessing with formail.
Wes