ASM coding - Checking battle command in use

Perhaps, can it be the direct page value? In the C2 bank, it is always zero and TDC is almost used to clear the two bytes of the A register. When the direct page is changed, it always is set back to zero afterwards.

The direct page can be different in the code in the C1 bank. You can try a TDC and check if the value returned to A is zero (two bytes). If it is not, it is the wrong value for the direct page and all opcodes related to the direct page will load the wrong value.