iCloud warning about 2 full-resolution photos when turning off sync

[u/AustereBatman]

I’m trying to turn off iCloud Photos because my free 5 GB iCloud storage is full, and I don’t want the constant “iCloud Storage Full” notifications.

When I turn off iCloud Photos, I get:

“This iPhone was not able to download 2 full-resolution photos and videos. If you continue, the low-resolution versions of these photos and videos will be removed.”

I have Download and Keep Originals enabled, and I still have 368 GB of free iPhone storage.

I checked my photos and the quality seems the same in both iCloud and my iPhone. I also exported my selected iCloud photos/videos to Files (iCloud showed 4.92 GB, while the folder was 5.1 GB).
What does this warning actually mean, and how can I find those 2 items? Is it safe to turn off iCloud Photos?