Has anyone had a problem losing e-mail messages after viewing on the iphone

Recently, I have lost a small handful of Yahoo messages. Seriously, they just vanished into thin air. The message would be there in my list of messages, but when I would open it on the iPhone, it would be a completely different message.

Initially I thought I had accidentally deleted them, but after searching once on an actual computer, I discovered that they were truly gone. I finally contacted Yahoo about the problem, and they said that it is a known issue - the issue being a user has a message, views the inbox on ios5, tries to view the message, but then the message disappears completely..."completely" being verified by use when logged in on a non-ios5 device such as computer.

So now I'm just careful. Fine.

Now my boss is telling me that he has had some of his messages disappear from our company domain through MSExchange. WTH?? We're having our Exchange host look into the issue, but I thought I'd do some investigating of my own in the meantime.

Has anyone else experienced this?

For the record, both of the phones in question are 4s iPhones running ios5 (naturally) on Verizon. Mine is a 64GB, acquired in November 2010, and my boss' phone is a 32GB, acquired in December 2010.

Any insight is greatly appreciated..