NLP metadata is missing

I wanted to make a smart collection with all my film photos, and I thought that the best and most reliable way is by using NLP metadata, Image status: Converted.

I have three questions here:

  1. It works for 80% of the photos, but there are 200+ missing this metadata. Why? And can I fix it somehow by not converting them all over again?

  1. There are few images with status: Not Converted, but they are converted in NLP from negatives. What this means and can I somehow convert them to “Converted” status?

  2. I have few photos taken with my digital camera (not in the scanning process, but some random photos), somehow ended up with the status “Not converted”. Not sure what happened here, but can I somehow remove this status, so it doesn’t mix up with my negatives.