OnBeginOverlap fails to get Value where OnEndOverlap succeeds

I have a Box Collision component on my pawn to keep track of how many outside actors are inside it (through a Blackboard value owned by that pawns AI). I add 1 when something begins overlapping and subtract 1 when something leaves.

But I couldn’t get OnBeginOverlap to work so I finally plugged both events into the same tree;

OnEndOverlap works without issue but OnBegin works some ticks while others it throws the following error message;

Error Accessed None 'CallFunc_GetBlackboard_ReturnValue2' from node MyFunction in blueprint MyBlueprint.

What gives?

The error you’re quoting comes from trying to call GetBlackboard on a Null object, or from that object (AIPlayer classed) not having a BlackboardComponent instance. I suggest putting a break point in your BP and debug the hell out of it (remember, when BP execution pauses on a break-point you can mouse-over pins to see their current value).



Thanks, I’ll debug this best as I can and get back to this thread if I solve it.