Hello Nox_A15,
I can confirm that this would cause a crash, but it’s an expected one if that is your hierarchy. What you end up with after following the steps in the original post is BP_Parent_Child and BP_OtherActor having a circular reference issue. The variable that you create in BP_Parent that references BP_OtherActor causes this issue. Since BP_Parent_Child inherits everything from its parent, this causes it to have a reference to BP_OtherActor as well, which has a reference to BP_Parent_Child, which has a reference to BP_OtherActor and so on.
What kind of crash message are you getting when this occurs? I noticed that it hasn’t been mentioned and there could be something in that callstack worth looking out for that could make this more obvious.