I would start by confirming that the problem *is* spamhalter. Disable it completely and see what happens. Then step through any active Content Control sets, and also your mail filters and autofiltering. Any of these may be responsible (though the final one is unlikely otherwise all of the messages would be redirected to the same place).

Likely there is some wording or phrase in certain of the messages (or headers) which is being picked up on and filtered. turn everything off, test, then re-activate bit-by-bit. Laborious but specific. Let us know what you find.

The mail filter on my Pegasus, V4.41, seems to have gone wacko.  It's not even close to being consistent or accurate. 

 I can receive four emails from a friend in the morning.  Two will go into the New Mail folder, and two will go to Junk or Suspicious Mail.  She forwards things to me, virtually all of them, so all four are treated the same at her end.  At my end they are treated differently, for no apparent reason I can see. 

 This morning I forwarded something to myself, from my primary email account to my primary email account.  I simply cleaned it up, and sent it from and to the same account.  It came back and was put into the Junk Mail account. 

 I've tried reclassifying in the Spamhalter settings, but have had no luck.  Spamhalter seems to be un-trainable on my system. 

How do I go about fixing this annoyance?