Same thing happens to me. My email account is AT&T's Worldnet. Most of the time when I delete an email on my iPhone, it deletes on the server too and does not wind up in my home inbox. I say "most" because lots of times I delete it, and it comes right back. Sometimes I delete it 3 times throughout the day before it's finally gone. It's like a boomerang. And yes, I have it set to delete off of the server. Most of the time it works, many times it doesn't. Aggravating.