Pair of Switch 2s have unlinked on only one console

I met up with a friend and linked consoles to share virtual game cards and on my switch I can load his games and play them with no issues.

However on his he can’t load any of my virtual game cards and I also can’t load them from my end onto his console as it says we need to pair again.

His Nintendo account on browser shows mine and his as the linked consoles but my account shows mine and his as options but when you click on his it’s unlinked.

Any ideas why this would unlink one console as I thought it only needed paired once? Assume there’s also no idea to fix this outside of meeting up again right?