When you and your team have the time and resources, look into this if possible. Thanks!
1.Project does not assume the properties of the file with 5.1 audio, it is always necessary to manually adjust the project properties. What is expected is that the project's properties assume the same properties as the file with 5.1 audio automatically, in the same way as with files with stereo audio.
2.In nested projects the tracks with 5.1 audio are converted into stereo tracks and when returning to the Master project there is only one stereo audio track. What is expected is that in nested projects the tracks with 5.1 audio remain and when returning to the Master project there are all the new 5.1 audio tracks.
3.Add Missing Stream for Selected Events restores only channel 1 of stream 2 to a new 5.1 audio track with all channels enabled. The Add Missing Stream for Selected Events option is expected to restore all 5.1 audio tracks with their respective channels correctly enabled.