Project tabs: Synchronize any parent projects... does not work an newer Hardware

[Rumario]

The Synchronize any parent projects when playing back subproject function does not work on my new HP Omen Laptop 15(model:en0263ng, AMD Ryzen 4800, Wín10 Home always the latest version).

If you press play, Reaper shows the message "sync with others" but does not start. After some seconds the subproject start playing but you can't hear the parent. But the parent is playing but not really, see the video I made. If you click inside the parent it starts really playing. Weird. First I thought this is a driver problem. But it is not. It's the same behavior with all different drivers/audio interfaces no matter whether Asio or DirectSound. For me this a very important function, because I use sub projects in every project multiple times

Otherwise, Reaper runs really well on the new Ryzen 4000 processors. It's really unbelievable how fast.


https://www.youtube.com/watch?v=nee_kJkDYEI

[Rumario]

As already suspected, no audio driver problem.

Basically it works!

But not always. It seems to be the case that if the sub project is longer than the main project and I want to play a part of it, the bug arise.

[Rumario]

I did more tests. It's definitely the length