Here is a video demonstrating the problem:
As you can see, there is something going on in the first session (the one I am trying to record into) that isn't happening in the fresh session (the second example). I'll describe the experiment:
In the first session:
I create a new track and record enable it with monitoring.
When low-latency is off I hear nothing from the DAW but I do see a green line indicating some signal coming into the record enabled track.
When low-latency is on I hear the guitar but I see no input level in the DAW (still the green line) and I see output level coming from the main output.
In the second session everything works as it should.
Help! This is an important session I need to get done and I'm stuck.
(working on a musical about being a veterinarian all done in StudioOne)
Edit: This only happens on Input 1! When I hook the same instruments into input 2 everything works fine. Huh?
Edit v. 2: Well now I have a workaround. If I drop the input from the settings tab and then bring it back in I am ok for a bit (though it mysteriously drops out again after a while). Convinced this is a bug.