Not all instruments are heard during play back...

The uploaded score for "I got you" by Split Enz does not play back 100% correctly.
Please see: https://musescore.com/user/32760932/scores/14592262

It was created with Musescore 3.6.2.548021803, rev 3224f34 on Windows 10:
OS: Windows 10 (10.0), Arch.: x86_64, MuseScore version (64-bit): 3.6.2.548021803, revision: 3224f34

The Problems:
- The "Prophet 5 " piano part does not play, and the hidden "pad" that is meant to reinforce the left hand of this voice also does not play.
- The "Farfisa" piano part also does not play back.

However, the "CP-80" piano part that enters on page 16 plays back fine.
Both guitar parts play fine. The bass part plays fine. The drums play fine.

***** The request:
***** Could someone please look closely at this file, and try to fix whatever is preventing the playback?
***** (I have always wanted a debug parser for mscz files to hunt down problems like this.)

I also have similar problems with playback on my laptop in the Musescore app. When a voice doesn't play, all I have to do is click on a note in that voice, and restart the playback, and that voice will work again for the rest of my Musescore session.

Now, I admit that I always post very complicated scores, but Musescore has always done a great job rendering the audio - search for my scores by user "Sean L122" (Oh, I live for the ratings, and I love each and every "In case you missed it..." notification!)

Thanks,

Sean
(Yes, I own an old Hammond L122.)