Fetch Messages Up To... doesn't work

Is the Fetch Messages Up To… feature supposed to work with IMAP accounts? I would think so, given my previous comments here

comparing Sony’s K-9 fork from 2018 to the current K-9. But it doesn’t seem to work at all. I would have posted this much sooner, except for another difference, the inability to see the email size at-a-glance.

I finally did some checks this morning. One 156K email of mostly text was pulled in completely when Fetch Messages Up To… was set to 4K. There was still a useless Download Complete Message button at the bottom. A 43K email from EBay also did the same. This is happening on the same Android 13 phone, and with Earthlink as my email provider. But I also use a local ISP for IMAP email with the same settings and get the same results. This ISP appears to be using Postfix.

Comments? Would a log file help?

Edit: Tested with 6.714.