It’s a combination of a “function” key (special for that keyboard) and another key that doesn’t exist on regular keyboards that outputs Ctrl+Insert and so on.
I am using a dvorak varient, but this happens even if I switch to qwerty.
I tested the keys using the key history function in autohotkey and found out that the Ctrl+Insert thing on my keyboard basically holds down Left Control and instantly (0ms) after pushes Insert, then releases Left Control after a few ms and instantly (0ms) releases Insert after that. I think this is what’s causing the issue. It’s working fine everywhere else though so I think the ms don’t really matter, just the order of the key presses.
I also found out that sometimes this actually works in UE4 (!), I think this is because sometimes the instantaneous Insert key press turns into a 1-2ms key press which somehow makes it work in UE4. Or it may be something completely different, I don’t really know. I guess this is hard to test for you as well…