@jan5 I was running into a similar issue and just diagnosed it, but judging from your comments it might have had a different cause.
My issue was I was using the coords argument to subset some of my fixed-effects parameters, but the set of coordinates I was passing included repeated values. This gave me a similar ValueError (though the shape it was trying to broadcast was (9, 2) rather than (9, 3) like you’re seeing).
Probably a different root cause as it seems like you weren’t using the coords argument, but sharing just in case it helps you diagnose your issue.