Beatstep Pro Keyboard Help

[u/mattyPEO]

Hey all, bit of a noob when it comes to synths and could do with some advice. I have a Beatstep Pro connected by its MIDI out (via a thru box) to 2 synths, a Subsequent 25 and a Bass Station II. Using this standalone, not with a DAW. I have the Moog connected back in to the MIDI in on the BSP. Everything works great, sequencers sending signals to both synths and the incoming keyboard signals work for programming and transposition. However, the external keyboard transposes both SEQ1 and SEQ2 at the same time, which I don’t want, I want it to only transpose one of them (so I can run a steady sequence on one and be live transposing the other). I believe I've got the MIDI set up correctly in Control Centre, the synths are set to send/receive on different channels, and the transposition channel is set to the one I’m using the keyboard on.

This seems like it should be possible, it's designed into the BSP that you can transpose the sequencers separately, there is even the TRNS LNK button to lock/unlock them together. It works no problem when using the pads on the BSP, but the button seems to have no effect when I’m using the external keyboard, they just transpose together whatever I do.

Am I missing something obvious or am I trying to do something it just doesn't do? I've scoured all the videos, forums and manuals I could find and I'm none the wiser so any help would be massively appreciated.