Load 8.0 project in 8.5->no audio unless fader clicked

I’ve had to completely reinstall my OS, Cubase and associated instruments due to a spiky realtime performance issue (docs elsewhere on forum). This solved that issue but now I have a new one.

  1. Open Cubase 8.0 project in Cubase 8.5
  2. Push play, MOST instrument and audio tracks all play back and meters move
  3. instrument tracks that are moving their meters are routed to a Group track called Music
  4. The Music Meter is not moving at all, No sound is audible from the Main channel which also has no meters.
  5. Switch of track automation for Main and Music Group track - sound is now audible.
  6. Turn on automation - sound ceases
  7. Turn automation off so you can hear things.
  8. For the instrument tracks that are NOT moving their meters, and do not have automation - left click and hold the mouse button down on the fader, sound occurs. Release the mouse in any fader position, sound ceases.

Windows 10 201511, Cubase 8.5 from full installer, Halion Sonic 2, Native Instruments Komplete Ultimate 9 with all available upgrades (Kontakt used in project and is one of the instruments not making a sound), Steinberg UR44 interface with latest ASIO driver.

If I make a completely blank project everything seems to work fine, but I need to load old projects.

Looks like this might be BON-14543 to me?

same thing i encountered. no workaround so far for me.