Apple Mail "rules" truncate the message body from mail from Microsoft Exchange

My work recently switched to Microsoft Exchange email, and I use the Apple Mail client (MBP, Apple M1 chip, OS 15.5) to read it. I had a slew of rules set up to sort my incoming mail, but since the switch to Microsoft Exchange, the rules sort the mail, but they only save the header info: no message body is saved. However, if I turn the rules off and allow email to accumulate in my Exchange inbox, then turn on the rules and apply them to everything in the inbox, all the mail is sorted and stored properly, header and message body.

It's almost as if the rules are applied as soon as the header info arrives, without waiting for the message body to show up. I've spent hours with various IT folks at MIT trying to figure this out, and no one has a clue. Any thoughts on this would be appreciated.