I've been playing around with this problem some more today and discovered a
couple of things.
1) The bug first showed up in mid-july. Maybe there was an office update
around this time?
2) There appears to be some threshold that is reached which causes the
incoming message to flip into plain text. Using a message created using
Outlooks HTML format, I was able to find the exact point in the message when
it would be converted to plain text (upon receipt). I then added text to the
beginning of the message, and it changed the spot in the email where the
issue occurs, by roughly the same number of characters (but not exactly). The
only conclusion I could draw is that there is some combination of formatting,
word count, styles, etc, that is causing the problem. Note: The message that
I used was received in the proper HTML format by others, so the problem must
lie in my Outlook's incoming message processing, not the outgoing.
3) Unless a lot of people are experiencing this problem, MS will probably do
nothing about it.
If anyone has any other ideas, please let us know! This is a very annoying
problem.