Reminders app iCloud synchronisation disappoints.
Yes. And it has for a long time. I like the app itself, its natural place in the eco-system over all my devices, and being able to share lists.
But anyway, I’ve lost count on how many times the synchronisation between me and my gf’s devices on our shared lists just “doesn’t happen”. It usually happens eventually, but can take a very long time. This leads to just taking screenshots off the list and sending to each other on iMessage instead, which really makes it obvious how ridiculous this is.