There's a good chance nobody has an answer. I've never experienced quite what you are describing, so I'm not sure what may be causing it.
You mention the buzzing noise here, and I have seen something like that. it's usually caused by an unregistered plug-in.
Amplitube is notorious for it. It may be loading as part of the default project template, so it would be present, even though you may not actually be using it.
I know it injects the noise but I don't know if it adversely affects the recording.
If that's the case, registering it is just a procedure, and does not involve any cost.
Try starting with a blank project.
Insert one audio track, set up your input(s), and output, and record a track.
Is the problem still there?