There is a reason I said this was consistent.
I checked on four different servers (feddit.nl, lemmy.ml, lemmy.world, and sh.itjust.works) and all of them reproduced the automatic download for only this post. Of course, this can be due to an error with lemmy's source itself - which is why I said it isn't necessarily malware.
Secondly, I did a non-trivial check of my network for MITM when the error first occurred - and there was no evidence of MITM. I also highly doubt that the browser itself is compromised, as it is up-to-date and is focused on both privacy and security.
I posted it as a warning for those to check their machines if the browser (or other mechanisms) didn't catch it. I am also not above reproach; it is okay to criticize my claims - but they were not made without reasonable cause.
P.S. The files were blocked from downloading (and I will not be downloading them) so I am unaware of their contents. If it is just PHP, then lemmy itself likely has a edge-case bug triggered by this post (which is bad). But I do doubt it is PHP, considering all other posts do not display this behavior.
People from the U.S. (and even parts of Europe) do not understand how corrupt, stupid, and unstable majority of the world is. It is genuinely unfathomable.
This does not excuse the fascism of the current admin, nor the war-crimes of the U.S. as a whole, but they are nowhere even remotely close to the likes of Moldova.