As mentioned above, I‘ve exchanged with our engineers, who analyzed your video example with the following outcome:
From your video we can deduct that certain AU plugins in your projects get stuck upon (or after) loading.
This is why they produce no sound and why the CPU indicator goes to 100%, which means that something (an AU plugin) holds up the Cubasis audio rendering.
Could it be that one or more of the AU plugins that you are using received an update around the time Cubasis 2.8.2 was released, and that the plugin’s update somehow causes the Cubasis rendering thread holdup?
In order to find the cause, we’ll have to narrow it down to just one AU plugin.
(1) Can you reproduce the issue with 2 projects that only use one AU plugin?
(2) Or can you send us 2 projects where the issue often occurs (when switching between them)?