After not being able to find event statistics (or PR) for the Zero Build Victory Cups I played in season 1, I came across the forum (linked at the bottom of this post) that discussed the issue and found myself also listed for the events as KBM.
I can confirm however, that both my duo and myself only use controller. We regularly played the Zero Build Console Cash Cups as well, and those are correctly listed under controller events. This leads me to believe there is a more widespread issue with these Zero Build Duo Victory Cups, where they are sometimes incorrectly listing as KBM instead of Controller for the players involved.
Example:
Event: Zero Build Duos Victory Cup
User: Mvxm
Date: Feb 09, 2024
Region: ZB NA Central
Placement: #3759