I noticed their event is “tentative”, maybe that’s why it’s not federated.
I thought of that as well, but the other instance I follow, events.hackeriet.no, also has tentative events that federate just fine (like DemoHack (TBA) - Mobilizon )
One reason why you might see only one group could be that the other has been created before you start follow this instance. I’m not 100% sure, but I think if you follow the group from your instance then it would appear (if you do so, I’d appreciate a feedback).
Both groups existed before I started to follow the instance. The same was the case for the other instance I follow, events.hackeriet.no, and all groups appeared from them. One interesting sidenote, though:
The reason I became aware of events.hackeriet.no, was that some groups from that instance suddenly appeared on my instance. It was only after that I started following the instance. That sound a lot like what happened here when groups from gjer.no appeared on solveig.plann.no without following (or at least that’s how it appeared to me – maybe @tobixen(Hi! by the way) can elaborate.
And I’m curious about the mail you received, was it a mobilizon generated email? Or maybe Solveig tried to get in touch with you, asking you to follow them
Yes, it was a Mobilizon generated email: “Want to connect? Events relevant for S/Y Solveig or its captain (solveig.plann.no) just requested to follow your instance. If you accept, this instance will receive all of your public events. [..]”
When I clicked the link and saw no following request on Admin →Instances, I thought maybe the request was removed. But still, some groups appeared on the site.
Anyway, the whole federation affair seems a bit messy and hard to control and understand, so I’m looking forward to some improvements.