The theory KaKaRoTo had was that why it works locally is that the same thing happens there, but foundry manages to clean up eventually because there’s no storage limit. On the forge, you hit the 500mb limit and then Foundry can’t actually solve it anymore.
You can try this by going through it locally and checking if the world size changes while the update occurs.
There shouldn’t be anything The Forge itself does to cause this, more like it becomes apparent, as you run out of space.
We’ve had other people having issues with migrating the latest pathfinder updates, where it’s simply doing too much, but not like your issue.
It’s likely we’ll gain a better picture of this over the next weeks, it seems like something might be up with the gamesystem itself.
Though, to be fair, you do have 200 commoners, all with their own items etc. I’m not sure what PF2 is doing while migrating, but it has to be related to it.
I did see that they forced an update to the bestiary on 1.13.2 for some reason, so that’s likely why the error occurred again for you. Though it might be likely that it keeps happening when larger migrations are done.
Anyway, try to check what happens to your world size locally, it might be too quick to fully keep track of, but you should see a huge spike in size, followed by a reduction soon after - and that spike probably goes over 500mb, thus the issues on The Forge.