Good, I am not alone.
I have noticed it from two different android phones connecting to a verizon.net mail account. It does not happen on the i-phone though. One of the phones is on my verizon plan and the other is my work phone via AT&T. I know it is not phone related since it is happening on different phones with different carriers. It appears to be a timeout issue. If the status of a large number of messages cannot be read within a ceratain amount of time, it marks the others as unread and your phone appears to have new mail that is 2 months old.
I have reset the port and server values as suggested from the on-line help info, but to no avail. Does anyone have any other ideas?