Check the code before reading

When I change DeciNumNum to 1 (to add in 10s instead of 1s) at first it seems the emulator (it's the same on hardware) doesn't register up and down inputs in that state, but when you spam the up or down button it sometimes (rarely and randomly) registers the input and adds a 10. I can change DeciNumNum back to 0 and add in 1s no problem, i checked the code plenty of times, and haven't found any issues. When i print the variables to the console everything works as intended besides adding 10s.