SOLVED:
Comunication between these two blueprints works fine the other way around. Found a couple of ways to solve the problem:
- Checking variables on GameMode from the HUD.
- Using an event dispatcher on GameMode and listening to it on the HUD.
- Interfaces, not very clear on how to implement it yet.
Took the first route, faster and easier to implement. Hope this helps someone falling in the same mistake i did.
ORIGINAL QUESTION: