Same here, I have a thread about it if you want to look there for the posters help.
Guys advice didn't solve my issue though. Mine is slightly worse I think, I rarely get notification PLUS it just won't Sync, Push or otherwise find any of my emails, no matter the combination of settings tried.
I only get my full emails when I tether the device, dunno why but this fixes the issue.
So who do we talk to about this? Is this HTCs issue or is there a 3rd party in this crime?