Mac Photos ask to import photos from iPhone that have been previously imported

My issue; I have had about 430 iPhone photos that the the mac Photos application thinks are new and need to be imported, but I know for a fact that they are duplicates of what is already in the Photos library.

This is driving me crazy and I am looking for a Solution / Fix.

Below is what I have tried, and did not work.

1. Since it appears that photos on my iPhone are the culprit, I completely erased the iPhone, expecting the problematic photos to disappear. I restored it from the recent iCloud backup, expecting the only photos on the phone to be those from the iCloud photo library, which may have been true, but the mac Photos app still recognized ~400 iOS photos as new and needing to be imported. Note: several apps required re-setting up user credentials, not fun.
   Erasing and restoring the iPhone didn’t work.
2. OK, I imported the problematic photos from the iPhone into a unique Photos album (iPhone Dups), which appeared to work OK during that session. My intent was to select the photos in that album and delete them. Well, the next time I connected my iPhone to the MBA and opened photos, those same problematic photos showed up as new and need to import.
   Importing did not fix the problem.
3. It gets worse. I imported those same photos again into the uniqe album, which resulted in having triplicates or more in my library and on iCloud. Next, I selected all but 1 token photo in the special album and deleted them. Went to recently deleted and selected the photos, them permanently delete. Trying to save iCloud space since I didn’t see a need to keep known duplicate photos around for 30 days.
   Waited a bit for the iCloud synching to catch up, closed the mac photos app, reopened and connected the iPhone. Now it is saying that there are 1400 new photos that need to be imported. The logic within mac Photos and iCloud Photo Library truly escapes me.
   Moving to the trash and permanently deleting did not work and made the problem worse.
4. I deactivated iCloud photo library on the iPhone and manually deleted every last photo from the phone. Problem photos should be gone, right? Repaired the mac Photos library using command-option. Soft reset and restarted the iPhone. Re-activated iCloud photo library. After completing the photos update, Had 4,787 photos and 111 videos on the iPhone photo app, which matched exactly to the mac Photos app. After letting everything sync up, mac Photos shows that there are again over 400 (to be exact 438), new photos on my iPhone that are new, but in fact they are duplicates of what already exists in the library.
   On the iPhone, deactivating iCloud photos library, then manually deleting didn’t work.

Several questions;

Has anyone seen this problem and found a solution, so that mac Photos doesn’t recognize duplicates that already exist in the primary library?

Any knowledge on what causes this problem?

MBA, macOS 10.13.3

Photos 3.0

iPhone 6s, iOS 11.2.6, 64GB

iCloud photo library is active

Photo Stream is inactive