I have the exact same error happening. It happens after I’ve been playtesting my game for a few minutes. It points to a line of code that runs several hundred times in those first few minutes and works fine obviously. And then it decides to stop working and crashes the whole editor. It points to a line of code that pulls a variable from a object pointer. on the lines above, I test to make sure that object is not null. I don’t know if it is actually null or not but it shouldn’t reach that line if it is!
I’m becoming more and more certain that it is a problem with the engine. I made all sorts of changes, renaming things, constructing things differently… Still get the same error and still only after I use the mechanic liberally without problem.