When refering to RPT i mean the mainLog one.
My buttonClick ctrlEventHandler was triggering 3 times. As seen in RPT lines 985,991,996.
Although i only added the handler once.. To circumvent that i added a
_control ctrlRemoveAllEventHandlers "buttonClick";
to the beginning of the EH.
After that you can see the EH being called once (RPT L1055) and after that when Arma previously would call the EH again.. it just crashes.

In short if there are multiple EH's attached to a control and you remove a EH that is in the call queue from another EH in that queue. Arma tries to access that EH after it was deleted.