Each key triggers all 6 voices simultaneously.
Sounds are good and a little fat.
It's not really heard when a ton of notes are played. If you can hear a 6-note cycling you've definitely got a voice malfunction. It could be that one of the oscillator is dying. I guess it can be repaired, but the repair shop will probably charge you for more than what the synth is worth. Here's another test - create a patch where the filter cutoff is set very low, so you have a dull and rounded sound.