TAL-J-8 Strange portamento behavior when enabled with polyphony

[teilo]

I'm getting strange behavior if portamento is enabled together with multiple voices. This is on by default on a number of presets, and it is causing some bizarre transitions. (See for example the Dave Polich Thriller Brass preset).

It seems to trigger almost randomly, and with unpredictable results depending on what's playing. Moving from chord to chord sometimes triggers it. Sometimes it doesn't. If I play a two-note chord, hold the upper note, and then move down a step on the lower note, sometimes, the portamento kicks in from the upper note, sometimes from the lower note, or not at all.

If I play two note chords one after the other, sometimes the portamento is getting picked up in reference to something I played two chords ago.

As a test, load the Thriller Brass preset. Set the release to 0 on both envelopes, and raise the portamento a bit. Now start alternating between 2-note chords after one another (one on each hand). Keep playing and you will see what I mean. With 0 release, there should never be note overlap so it should kick in consistently, but it doesn't. The portamento works at first between the two chords. Then all of the sudden it stops working. Moving to two different chords, and it starts working again, but then stops.

All in all it's very erratic.