USB host issues with MC6 Pro and MC6 MKII

I have an MC6 MKII sending Bank Up and Down messages to a MC6Pro. I am also using the MIDI Host on the MC6Pro to control my Android Tablet and for my Tablet to control the MC6Pro. When the Android tablet is connected to the MC6Pro Host port, the Bank Up and Down messages from the MC6 MK II seems to create instability with the CC messages being received (even though the MIDI monitor only displays a single message being sent) and the MC6Pro moves two banks, not one. When I disconnect the Host connection on the MC6 Pro, the Page Up and Down messages are stable and it works as it should (one bank up or down at a time as pressed).

I have also tried using an external MIDI host (instead of the onboard MC6Pro Host) and the issue is replicated.

The MC6 MKII MIDI out DIN is connected to the MC6Pro 3.5 TRS MIDI input.

Why is this happening?

Did you disable midi through from 3.5trs to usb host?

Yes, I have this configured.

Is it possible to try going from the MkII into the Pro via 5 pin DIN, adjust the settings accordingly and try again?

Unfortunately I’ve tried that too.

It sounds probably that the Android tablet is mirroring the messages back to the MC6 PRO. On the MC6 PRO, is the MIDI Thru settings set to send MIDI from the 3.5mm MIDI Input out to the USB device (or Host port, wherever the uHost is connected to)? If so, to troubleshoot can you try disabling that and see if the issue persists?

Thanks James, I will try that and see how it goes.