DSKY buttons '8' and '9' do not work

I built this and am running it on my Galaxy S9, but the "8" and "9" buttons do not work on the DSKY. I tried looking through the code to figure out why, as I know they are `010` and `011` in Octal respectively. No luck finding out what's going on.  The Android logcat shows that I pressed 8 or 9, but the DSKY says `OPR ERR` anytime I press them. Any ideas?