I think that I've fixed this. The cause had to do with @Saffith 's changes to cheat refills.
I'm going to need to re-write a refill system that uses modifier keys, instead.
Here's the commit:
https://github.com/ArmageddonGames/Z...23ed738bcf49fb
Removing those two calls negated this issue, so, it's time to find a different solution for non-overlapping key bindings.