This might be a bit of an edge case, but I've just hit an issue with the native-mux feature where using both a jump-host and agent-forwarding at the same time fails; the agent forwarding does not work and there's no SSH_AUTH_SOCK at the destination. Switching to process-mux resolved the issue (but obviously the performance is not as good when multiplexing).

Agent forwarding works fine on native-mux if a jump host isn't being used at the same time 🤷‍♂️