@tuttle @lnxw48 I think this might be related to what @gargron has experienced on #Mastodon. The <content> element being empty/broken/something.
My guess it's got something to do with the instances that generate these errors. Something aborting the inclusion of <content> data. Oddly enough it only appears occasionally (otherwise it'd be rendered incorrectly in the Atom representation: https://status.vinilox.eu/api/statuses/show/4426688.atom
...but this assumes that if content is empty, !gnusocial falls back to the title property when parsing. Which I can't say I am 100% certain of without looking at the code.