Crash on 93% loading editor - when adding actor to blueprint

Hello guys,

This is a weird crash problem that I ahve.
By just adding one superactor(or child actor) to a blueprint, the editor crashes at startup.
I have 3 other child actors of the superactor type inside the blueprint, and they work.
Even if I just add the superactor, which contains only 3 unimplemented functions and a varaible, it crashes.

Since there is nothing executed in the actor, it seems that by simply adding this class type, it crashes (have tried adding a new empty actor type, it works)

Any ideas?, thanks.