Animation Blueprints which contain a shared transition used to transition between two animation states will be marked as "dirty" every time the blueprint is compiled and re-opened.
Result: you will notice that it has an asterisk in the Content Browser as it has been marked dirty even though nothing has changed.
Expected: No asterisk, Blueprint would compile clean.
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-74589 in the post.