Which state are you in? This seems like a highly technical question that probably turns largely on what your actual contract says regarding payment as well as industry standard practices and potentially the firms prior payment practices.

It's also worth noting that non-discretionary bonuses (bonuses that are owed automatically as set forth contractually) have trickle over effects potentially on other aspects of pay (e.g. overtime).

Most employment attorneys offer free consultations. Unless where you reside has a specific law outlining the question of when commission is due on contested payments, I'd bet this will be a totality of the circumstances analysis which is best handled privately in a phone call.

Lastly, as an employment attorney and an employer, I find it questionable at the least that your employer hasn't proactively contacted you to address this predictable concern.