Might be related to an operational issue on one of the two Onionoo hosts. I'm working on that, but it will take a few hours. Will post here when it's done, and then we can see whether issues were related.
The situation of two concurrently running updaters isn't really something we can test for in order to return an error. What would help is using a lock file, which we did in the past but which had the issue of not running the updater in some edge cases. And what would really help is switching to a database which can handle concurrent access much better than the file system. But that's out of scope for now, so we'll just try hard not to screw up.
Glad to hear it's working again. And thanks for creating this ticket! Closing.
Trac: Status: needs_information to closed Resolution: N/Ato fixed