Automatic deck selection for lighting not working correctly (DJM-750MK2 RB-DMX1)

I have an RB-DMX1 connected to a DJM-750MK2 with 2x CDJ-2000nxs2 connected to channel 2 (Deck 1) and channel 3 (Deck 2). The mixer is running the latest firmware (1.0.5) and I am using Rekordbox 6.5.3 (also the latest release).

As of Rekordbox 6.5.1, automatic deck selection should be implemented: https://forums.pioneerdj.com/hc/en-us/community/posts/900002099766-rekordbox-ver-6-5-1-has-been-released-March-2-2021

However I cannot get it working properly. I have my crossfader assigned so Deck 1 is my A (crossfader left) and Deck 2 is my B (crossfader right). The audio works correctly. But the deck selection appears to be reversed - if I move the crossfader over towards A (Deck 1), it switches the deck to Deck 2 and vice versa.

In addition, this only works if both faders are fully up. If I have the crossfader moved to the left (so Deck 2 is - incorrectly - selected) but then touch the volume fader for Deck 1, it reverts the channel to Deck 1.

You can see a video of this behavior here: https://youtube.com/shorts/rG0WV56XCrI 

Am I missing something in configuring this, or is this a bug?

Hoping to play a show with this setup on Friday so any help would be appreciated.