I'm having the same problem with Rogers in Canada. It seems to only affect gmail bis, not yahoo. Rogers technical support hasn't heard of it before, so they just gave me a reference number to call back... they just removed the account and reattached it to my BIS and told me to cross my fingers. It has happened about once every month for the last couple of months, both times on a Saturday...
So the ghost emails happened to me again today Aug 14. Pretty well exactly 14 days since the last time... My technical support guy noticed that the REFID of the "new" messages were different than the "old" messages, so Rogers Blackberry BIS thinks these are new messages and forwards them through.
He suspects Gmail is changing the ID of the messages regularly. They could be moving some people's data around as they add or remove capacity, compress or decompress data, change servers, who knows.
Gmail doesn't let you create folders so you can't move sent messages there to minimize the amount of email that would be resent.
The only solution is to every so often go into your gmail settings and select "Enable POP only for mail that arrives from now on"
I will probably have to do this every few days because I get about 10 emails a day. Obviously this is very annoying. I am seriously considering switching to yahoo because of it.
You can archive your GMail and that will prevent this from happening. Seems like someone said they setup a rule in GMail to archive new mail automatically but I haven't done that myself.
