MIDI woes (part 1)

[Almost Aviation]

I am having persistent problems getting my NDLR to work consistently at a basic level. I am using it with an iPad and I have successfully routed the four modules to various synth apps. I have done this using port 1 and channels 1 to 4, although I have also tried using individual ports (1-4) with all channels (omni) selected, or even port 1/channel1, port2/channel2, etc. I don't really understand what the ports are, but in any case it makes no obvious difference to the following behaviours.

I am persistently getting a lot of stuck notes. Now I don't yet know whether this is down to the NDLR or something on the iPad setup, but in exploring it I have zeroed in on another, perhaps related issue I have noticed from day1. That is that I sometimes press a chord change button but even though the NDLR screen changes to show the new chord, the chord doesn't change. In fact it's worse than this, because sometimes the chord changes for one part (e.g. motif1) but not another or others. I have captured this with some MIDI monitor screen shots.

Here's what happens when I press the Pad button to start. The screen shows the chord as Ic in white and it plays a C major chord. So far , so good. But now I press the IV chord button. The NDLR screen changes to show the chord as 'IV F' in white, but the sound doesn't change. Here's the monitor - the Pad part is the leftmost column and the MIDI messages are shown with the most recent at the top:

   

Now I press Pad again to stop, but it looks like only one OFF action is sent. Here's the monitor:

   

This leaves some notes stuck on. I can clear them with shift+panic. Now I press the I chord button and Pad again, but I get an unexpected sequence of OFF/ON actions (I have cleared the log screen so only the new messages show):

   

And finally, here is the aftermath of the same problem but with the Motif1 part also running (column 2). You can see that Motif1 has been transposed to play an F chord, but the Pad has not:

   

Does anyone else see this?