Mail bug? Are others experiencing this?

I honestly do not know what I have done that triggers this, but it's happened 2 times in the last few days. I get the emails (pushed with gmail) just fine, but then later it will say "(No Sender)" where the name should be, even though it was displaying the name a few moments earlier. Another thing that's strange is it doesn't happen to all emails I get (which averages 20 a day), it's only happened to 2 of them - and not from the same sender.

Has anyone else experienced this?