This is due to Kotlin version is stuck at 1.3 at the time of writing this solution. However, 1.9 has been enabled now and the above warning should not happen again.

See the keypad image in the description, adjacent to 9, there is only 6 and 8.

As there are different languages available, it's best if you actually type out specifically which test input you are having a question about (for ex the "third" test on Python is with the digit '0' so obviously not the one you are talking about).

Is the test that you are referring to the one with input = '369' ? Then '333' isn't valid because the last '3' in '333' is not adjacent to the '9' in '369'.

after you jump back to the previous dec a, you move forward to jnz, which is effectively a loop until a is 0. Then you ignore the jump and move to the next instruction, which increases a (now 0) to 1.