Airtag showing different locations depending upon which device I use

After using my AirTags mainly for 'play', today I had need for a 'real' use for the first time. The airline off-loaded one of my bags as the plane was overweight... Thanks Iberia! :-(

But... while my phone tells me the suitcases were last seen 9 hours ago in Madrid, I happened to look at my MacBook and discovered that my cases were in Paris 60 minutes ago.

How is that possible? No amount of relaunching the apps makes any difference.