Dary1, it's possible to gain stage tracks using the Gain plugin (Utility > Gain). I can see that Audio 22 track has no effects, so you could just insert the Gain plugin and go from there.
The reason why you are not able to do so in the region parameter box on Audio 22 is that audio regions there are organized in take folders. So, another option for you would be to flatten the take folders, and then use the region parameter box for gain staging. Flattening the takes is a destructive action, because it creates a new audio file, so you might want to preserve the original take folders by duplicating the track, making copies of the take folders, and flattening the copies (and then gain staging them in the region parameter box).
As for the take region on a mono track being bounced in stereo, there might be a stereo effect plugin somewhere in the signal path. If you could post a screenshot of the Mixer, it would be easier to determine. Now I can only guess.