When changing the variable name of Parent Blueprint, only Child Blueprint existing on the opened level becomes Dirty.

Changing the variable name of the parent Blueprint also effects the changes to the child Blueprint, but the Dirty result changes depending on whether it is placed on the level.
This means that Child Blurprint's Dirty is inconsistent.

1. Create a parent Blueprint that base class is Actor, and add a variable. (BP_Parent)
2. Create a child Blueprint that base class is BP_Parent. (BP_Child1, BP_Child2)
3. Place BP_Child2 on the level.
4. Restart the editor
5. Change the variable name created in Step1.
At this time, BP_Child 2 existing on the level becomes Dirty, but BP_Child 1 is not Dirty.

Attached a reproduction project.
When change the name of the BP_Parent variable (Value), it will be reproduced.