Constant crashing when compiling function override blueprint

Upgraded my project to 4.12 today, going through Unreal Engine’s Drag and Drop with UMG tutorials.

My exact setup: I have a widget named “InventorySlot” which contains a button, a size box and an image.

In the event graph, I go under the functions section, select Override and “On Drag Detected”. Double clicking the function brings me to the function graph.

And if I press “Compile” now, it just crashes.

I have the files related to the crash saved, not sure what would be helpful to review.

If I go back into the project, I will see that “On Drag Detected” is not there. If I had pressed Save before attempting to compile, it would show up but would complain about having a parent with a different signature… so I would try to remove/re-add it just to crash again.

This is incredibly frustrating and I would appreciate any help in figuring this out.

Edit: This is not the only place I am currently crashing - there is a lot of crashing going on, mostly when editing UMG stuff. I was hoping we could take this one simplified scenario and isolate the reason for it.

Edit 2: Found out this is a known issue and will be fixed with a hotfix: Random crashes on UMG compile - UI - Unreal Engine Forums