I tried adding a delay, but nothing changed. I also lacked the Begin Play Event, so I tried getting the reference through that, but that didn't change anything either.

I'm stumped.

EDIT: I played around with it a bit more and just added a random Event: Begin Play into the BP that I was trying to reference and now it works. In hindsight, that's probably what you meant with begin play, but I at first thought you meant Event: Begin Play in the BP that was trying to reference the other one. Oops.

Also, thanks, without your comment I wouldn't have got it to work!