It’s faster to explain this one with a video, checkout the video in the zip file.
The executive summary is, when selecting parameter types for a blueprint function, selecting them directly is fine, but if you filter the list, then select them, it goes boom.
P.S. Here is the assertion text printed at the end of the video that gets cut off. It doesn’t look very useful, but I figured I would post it anyhow.
[0051.48] LogK2Compiler: Overridden flags for Actor class ‘SKEL_Tutorial_Door_C’: CanEverTick False CanBeDamaged False
D:\BuildFarm\buildmachine_$$depot$UE4-Rocket\Engine\Source\Runtime\Core\Public\Templates\SharedPointer.h(696): Assertion failed: IsValid()