The new DeNoiser and DeReverb don't work well the first part of the audio clip.
There are some of these results on You Tube. For example the first part of the audio of the videos of the Video Revealed and Jason Levine videos have these audio problems, I think because they are using these new tools. ;)

Jason Levine: https://www.youtube.com/watch?v=eZsbFuuEy30

Video Revealed: https://www.youtube.com/watch?v=Pkla0IPt8ck