I can’t re-produce anything, because I don’t run Lemmy on my server. It’s possible to infer that’s it’s related to the software (because LW didn’t do this when it was on 0.18.5). However, it’s not something that, for example, lemmy.ml does. An admin on LW matrix chat suggested that it’s likely a combination of instance configuration and software changes, but a bug report from me (who has no idea how LW is set up) wouldn’t be much use.
I’d gently suggest that, if LW admins think it’s a configuration problem, they should talk to other Lemmy admins, and if they think Lemmy itself plays a role, they should talk to the devs. I could be wrong, but this has been happening for a while now, and I don’t get the sense that anyone is talking to anyone about it.