Tailscale machine sharing issue with Jellyfin

[ClearEconomics6]

Hi, I'm experiencing some odd Tailscale machine sharing behaviour when accessing Jellyfin and wondered if anyone might have a solution.

• I'm using a Terramaster F2-423 as a home media NAS running Jellyfin on TrueNAS Scale, which is working perfectly on all devices connected to my home network.
  
• I've installed Tailscale on both the NAS and my Pixel 7 smartphone, and I am able to see my NAS as a machine and also access Jellyfin with no issues when not at home (i.e. on cellular or other wifi networks).
  
• Tailscale ACL is set to default (allow all), no exit nodes.
  
• I've shared the NAS (using share machine invite) with my partner, who is able to see it in both her Tailscale app installed on her Pixel 5 smartphone and the web portal. Note the machine name in my Tailscale app is how I named it and the machine name in my partner's Tailscale app is the Magic DNS version - the IP address of both is the same (100.XXX.XXX.XXX). I assume this doesn't matter.
  
• HOWEVER... my partner can't log into Jellyfin on her smartphone when not on our home network. No available servers appear when scanning, and typing in the Tailscale NAS IP doesn't work.
  

Any ideas on how to get my partner's Jellyfin to recognise the NAS? Instinct tells me this is probably a Jellyfin issue, but I can't see how or why because Jellyfin on my smartphone works fine remotely.

Thanks!