WTF: Event Signature Error: The function/event 'xxx' does not match the necessary signature - has the delegate or function/event changed?

[akaPrometh]

Ok, got it. Dumb as always.
Cannot have fields called ‘self’ in an event declaration.
In my event I was doing:

DECLARE_DYNAMIC_MULTICAST_DELEGATE_OneParam(FEventDelegate_AGrapplinHook_OnThrowGrapple, AGrapplingHook*, self );