Missing and duplicates when syncing photos from MacOS 15.5 to iPhone iOS 18.5 using Finder

MacOS: 15.5

iOS: 18.5

I'm experiencing significant issues syncing photos from my Mac to my iPhone using Finder. Several photos and videos are missing on the iPhone after sync, and I also notice that some photos are being duplicated.

I've been using this workflow for years, but these sync problems have only started recently.

Here’s my process:

- I import all photos taken on my iPhone to my Mac Photos library by connecting the phone to the Mac and using the Photos app’s import function. I select “Delete items after import,” which removes the photos from the iPhone camera roll.

- After cleaning up and removing unwanted photos and videos on the Mac, I select my favorites and use Finder to sync the favorites, along with all photos and videos from the last year, back to the iPhone. Here are my settings

Any idea why some photos and videos are not syncing and why some are being duplicated?

When I run sync again, it sometimes randomly syncs a few more photos or videos.

I’ve tried restarting both the Mac and the iPhone, but that hasn’t resolved the issue.

My iPhone has plenty of available storage, so space is not the problem.

Appreciate the help.

[Edited by Moderator]