On 09/21/18, A. Dumas pondered and said...
 
 AD> No, your server/gateway adds its own timezone (without time) to the
 AD> client's time (without timezone). That's the whole problem! What I

I'm not sure this is correct.

 AD> message. So, bin the date/time header the client sent you and simply
 AD> replace it with date/time/timezone of the server (your gateway) from the
 AD> moment you're processing the message.

I think this is/was what the software was doing before I removed the (correct)
+1200 (UTC/GMT) timezone info from it in recent days. I'll need to do some
tests to confirm / deny. 

--- Mystic BBS v1.12 A39 2018/04/21 (Windows/32)