fetchmail quirk? - Things That Fell Out of My Head — LiveJournal

So my mail arrives at my host server, and it's there in my inbox.
From another server, where I prefer to keep the mail, I use fetchmail to grab the mail via IMAP, and remove it from that other server if I've successfully retrieved it.
For the most part, this works excellently.

But lately, I've been encountering a situation where certain emails (usually ones with many lines of quoted messages; replies-to-replies-to-replies...) are rejected as "exceeding maximum size" (despite being only medium-sized) ... and deleted! from the server where I'd already received them and they were fine!

From the fetchmail manpage:

SMTP/ESMTP ERROR HANDLING
       Besides the spam-blocking described above, fetchmail takes special actions on the  following
       SMTP/ESMTP error responses

       452 (insufficient system storage)
            Leave the message in the server mailbox for later retrieval.

       552 (message exceeds fixed maximum message size)
            Delete the message from the server.  Send bounce-mail to the originator.

What? How is either of those things the right thing for fetchmail to do in this situation?