Hope I explained it clearly enough... Play the chord,  press/hold shift (left side shift),  release the chord,  release shift =

I'm going to have to try these. Long decay chords sound terrible when you release them. I always roll my fingers off and leave the lowest note to trail off.

Yeah,  I noticed that it matters which order you release them,  but it's just easier for me to use the SHIFT trick.

Its been awhile since I last used Cynth, but I thought it was an issue of how you release the notes. In what order you release them, compared to which order you pressed them. Whether you think you pressed them all at the same, time, the Commodore will have seen them as individually pressed down.

As you said, the highest note plays again, but I think you can also release the notes in order from lowest to highest by rolling your hand off of the keyboard. If SHIFT works then, thats cool too. Try what I suggested, but I said I haven't used it in awhile.

I believe what you are describing is a well documented SID chip flaw. The chip was rushed during its later days of development and some issues were left over as a result.

One of these issues was that the Sid chip having after played a note never had actual zero point in its amp envelopes resulting in the notes never fully turning off once a sound had been played.

I've noticed when using Cynthcart with the release set to long,  that when you release a chord,  it sounds sort of cut off and weird (at least on my Cynthcart). But by using this trick you can let those chords ring out!

Say you play a chord.  Normally it will sustain as long as you hold the keys down but as soon as you release the chord,  it sounds weird... It sort of plays the highest note again...hard to describe.  But if you hold down SHIFT after you play the chord,  and then let go of the SHIFT button,  it will sound fine... The notes you played continue to ring and fade away appropriately. 

It has to be the SHIFT button on the left side of the keyboard,  not the one on the right. 

It also acts as a sort of HOLD feature... It will hold the note/notes that you played until you release it.

I know this sounds sort of strange,  and I'm not sure if everyone's Cynthcart behaves this way,  or just mine.  If anyone wants to verify this behavior on their Cynthcart,  be my guest!