Find My via Safari from my MacBook Pro is 19 hours lagging behind

Hi I'm tracking my iPhone as it heads to Dublin for a repair. I can track it pretty much real time from another iPhone or my iPad. (Both associated with the same Apple ID). But when I check on my MBP via Safari, the location is 19 hours behind reality. This is strange to me. I'd have thought that cloud syncing meant cloud syncing. It's also a bit concerning because I'm old school and would always reach for a decent screen and a proper keyboard before faffing around on a small screen and if this was a real lost phone situation I'd be using rubbish data to help me. Can anyone explain this please?