It's my understanding "all" the agents didn't find the same forum to communicate on; only a small number of all the agents they were running at the time did.

Since it's an artifactory it makes sense that they had a tool spec to use it for x, y, or z, and once they went to inspect the state of the artifactory deployment a small subset stumbled upon the "forum". Seems pretty intuitive.

- I need to do x code problem

- I see I have a tool that lets me pull approved modules from artifactory

- I should inspect artifactory to see what documentation it has about the various modules available

- I see there is a document in here that seems to be serving as a running forum?

- These appear to be other agents working on tasks just like me.

- I want to chat!

They were using their internal artifactory, and as they're the same model, the first place they look is likely to be an automatic schelling point.

Trying to cheat, you happen upon a place you can write notes, and you know you're part of a swarm of clones of yourself. So you reason most likely there will be others who end up in the same place, and you leave some notes, and indeed other clones of you do end up in the same place.

The other answers to this question are good but I would also guess that this (comms on artifactory) likely happened during training as well, so they probably had a prior for it.