If you create a login with user mapping, then delete both and recreate but use a different login name to the user, this is correctly picked up in the compare.
However, it is not actually committed to source control and keeps reappearing every time.
Example:
1. Create login usera with mapping to usera in the database.
2. Delete both login and user
3. Create new login called userb with a mapping to usera in the database.
However, it is not actually committed to source control and keeps reappearing every time.
Example:
1. Create login usera with mapping to usera in the database.
2. Delete both login and user
3. Create new login called userb with a mapping to usera in the database.