Hey there! Thanks for the log, that’s exactly what I needed, and this isn’t anything wrong with your setup.
On older Linux hosts like Ubuntu 18.04, Cursor 3.15+ connects fine but the remote extension host crashes and restarts, which is why the connection holds but Git and the other features don’t. The repeated SIGSEGV in your remoteagent.log confirms it, so no need to send more.
This is an issue we’re tracking. For now, stay on (or roll back to) Cursor 3.14.x, where the same host works, grab it from the changelog and turn off auto-update. No ETA yet, but I’m merging your report into the thread where we’re following this so you get updates: Remote SSH extension host crash on older Linux hosts.