The Delete Assets window's list of assets that are available to replace the references to an asset that is being deleted returns additional assets that are not valid replacements.
The provided project contains 8 Blueprints, a Parent, ChildA and ChildB which inherit from Parent, GrandchildA and A2 which inherit from ChildA, and GrandchildB and B2 which inherit from ChildB. The last blueprint is a ReferenceBP that references one of the blueprints.
In the reproduction case, all blueprints in the level are listed as possible replacements.
Regression?: No
This occurs in 4.20
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-69417 in the post.