OK you're right. There is something wrong...
Seems like it's not random at all and that you reproduce each time you switch from 3 to 6 voices for this patch, no ?
If you want me to give a try I really need this patch. Can you save it in your default preset and share DEFAULT.CMB. You can access it from the PC without opening the preenfm2. See (1) here : http://ixox.fr/preenfm2/manual/upgrade-firmware/
I have no idea what's going on, so i have some questions to try to understand.
1. Is if a filter (LP, HP ?) activated ?
2. Is tools>Set>Midi thru on or off ?
3. Does it only happen with preset from DX7 sysex ? or with regular preenfm2 preset ?
4. When out of tune. If you press 6 keys at the same time. Does it have the same result as INST+MENU ?
5. Is Tools>Scala>Enable ?
And a last one :
6. Is the problem still here if you set Tools>Set>Receives to NONE ?
There's no point in sending you a file because it's random. One minute it's fine, then next patch is out of tune, 30 mins can go by and it's fine and then another patch out of tune etc. It's not just one specific patch.
1. Is if a filter (LP, HP ?) activated ? - When I load a patch, filter is off.
2. Is tools>Set>Midi thru on or off ? - Yes it's off
3. Does it only happen with preset from DX7 sysex ? or with regular preenfm2 preset ? - Nothing so far has on regular preenfm2 presets but i haven't played them much but will do more testing on them today, so far it's just been dx7 .syx files randomly.
4. When out of tune. If you press 6 keys at the same time. Does it have the same result as INST+MENU ? - No, the only fix so far is hitting inst+menu or turning "voic" parameter down to 3 or less.
5. Is Tools>Scala>Enable ? - No it's not, I checked a few times.
And a last one :
6. Is the problem still here if you set Tools>Set>Receives to NONE ? - It's set to NONE