Except I had to manually delete two folders from the config.xml, as when I tried via the web GUI they kept coming back even after I unshared them from all the other nodes and tried again.
Coincidentally, both of these folders were the largest.
I restarted the browser a few times before I manually deleted the folders, so I reckon the problem persisted past that.
In other news, I’ve just upgraded a different node and I’d no problem deleting the two folders on that one.
Both are ARM machines, the one I had to manually delete on is an Odroid XU4 which doesn’t get its updates via Syncthing itself instead it’s plain apt-get.
The other which had no problems with the deletion is a Raspberry Pi which uses Syncthing’s own upgrade route.
Otherwise, I don’t think there are any major differences between the machines.
I’ll be adjusting & upgrading a few more nodes today - so after that I’ll log a github and keep you posted.