I’ve done a little poking around. I too was getting weirdly formatted messages — more of them recently.
I get the daily digest. I use (mostly) Apple’s Mail, most recent version, to send and receive messages.
Turns out there are three choices for formatting when you subscribe to the digest version. There’s plain text (which I had been using), MIME format, and HTML.
I changed to HTML. The next digest came through looking gorgeous, nice table of contents at the top, links to the individual messages below. The problem was that I got only the titles of the messages, not their actual content. There were what appeared to be links from the message title to the actual message, but double-clicking the link did nothing. If I copied the link and pasted it into my browser, I got directed to a page that said it was just for the gummint and I wasn’t entitled to access it.
Interestingly, when I looked at the raw source of the email, it DID have the actual message content in it. So maybe for this particular bug the problem is with Apple’s Mail.
I’ve switched to MIME format, and will see tonight whether or not that gives me an improvement over the plain text version. If not I’ll switch to getting individual messages for a while and see what that does.
If you’re having formatting problems as a receiver, you might check out your formatting options and try changing them. Listserv.loc.gov.