I have the same problem with my A-190-2 - I would like to be able to use Last Note priority, but it doesn't work as I would want it to. 

Since releasing a key doesn't return to playing a previously held key, hitting the edge of the next key by accident kills the note I wanted to play - it stops immediately, and doesn't resume when I release the key I pressed accidentally.  E.g. I try to play C, but my finger also catches the edge of D, momentarily, resulting in a brief blip, then silence.

I'm a terrible keyboard player, so I do that a lot.  I settled for only using High Note priority, but that's not ideal because I also wanted to use the A-190-2 to control the filter of other synths, to provide velocity, but that doesn't work if the A-190-2 can't respond to notes in the same way as the synth I'm using it with.

I assume the A-190-2 firmware can't be updated either, but if it can, I would very much like to know, even if it involves replacing a chip - so long as it's one that's in a socket.

- Andy