[bug] No engine or cockpit sounds & multiple MSFS 2024 instances in audio mixer

Do you have the same issue if you follow the OP’s steps to reproduce it?
• Yes, just start any flight with, in my case, the C172.

Provide extra information to complete the original description of the issue:
• For me this happens with the C172, but not, for example, with the XCub. So my audio settings are not the problem.

If relevant, provide additional screenshots/video:
• NA