404 Not Found, bad gateway?

Hey there,

I’ve been having some major issues with this site over the last week or so.
It mostly happens when I try to hit the very last pages or the ones just before them in a thread; the older pages seem to load without any drama.

I keep getting hit with a "404 Not Found" message.
I'm attaching a screenshot here.

I'm running Safari with AdBlock active.

The weird thing is, if I switch to private browsing mode, everything works perfectly fine.

In all my years using this forum, I don't think I've ever run into this specific headache before.
Does anyone have a clue what might be causing this mess?

Best,

Update:

It looks like all those issues disappear once I actually sign in.
Anyone have any insight into why that would be happening?

double