We've noticed in the last few days that for some of our users, Outlook 2010 is blanking the subject lines on messages sent, if during composition the From address is changed.
For instance, an Outlook user with multiple accounts might compose a new message (or reply to an existing one). and enter a subject line. If the From address is changed, the message still appears to be okay, but when the message is sent, the recipient receives it with a blank subject line. In the sender's Sent Mail folder, the message will also have a blank subject line.
This does not occur if the user does not change the From address during composition.
We're running Outlook 2010 (32-bit, version 14.0.6025.1000) SP1 MSO (14.0.6106.5005). All up-to-date with patches. Running with Exchange Server 2010 (version 14.00.0639.021).
Has anybody else seen this behaviour? Any fixes? About to go looking through recent Outlook patches; perhaps one of these has caused it?
PS. We haven't been able to identify any removable patches that might have caused the issue. It's still occurring.
Also note that it is not affecting some users (with slightly different versions of Outlook).