Outlook 2003 signature issue

[k1pp3r]

Has anyone run into an issue with outlook 2003 disabling the signature after you open a plain text email?

Breakdown of what happens

Create new message, signature appears
Open a plain text email (from blackberry or other phone)
close plain text email
Compose new message in outlook, signature no longer active
go to options > Mail setup > signatures to re-enable
compose new message in outlook, signature is back.

Ran a detect and repair, same results. Tried a new signature file, it worked normally for a few days then started the same thing.

Anyone have any ideas?