I’m back in the realms of photos not syncing from my Photos on my Mac to Photos on my iPhone. Got a photo album with 65 images in, around 50 Sync, the rest don’t. If I deselect the album in Finder, Sync so it removes, then reselect and re-sync, I get more photos on the phone, -maybe 55 give or take-, but some of the ones that are now missing were ones that Sync’d initially. They don’t even appear in the right order.
Had this issue a few years ago and one update it just fixed itself, but it was like it for about a year. Back to square one again 🙄