Heya! Sorry for replying so late. What I was referring to seemed to be a keyboard issue -- I just used the normal singular bindings, and the issue's stopped now that I'm using a new keyboard. For context, though, the issue was that sometimes tapping *both* keys simultaneously caused one of them to not be registered. When this happened, letting go of the key that didn't register would register a "tap" at that moment. Even though I only noticed it in this game, it seems like it was a hardware issue instead of a game issue.
In another note, I would totally support the addition of more control schemes! When I play this game, I use DF JK, with the keys being bound as ZX ZX.