Did a quickie test, and here's what I got.
With "Mute previous takes"
enabled:
MIDI - Both existing takes and loop-recording passes are
muted in the punch region.
Audio - Both existing takes and loop-recording passes are
muted in the punch region.
With "Mute previous takes"
disabled:
MIDI - Both existing takes and loop-recording passes are
audible in the punch region.
Audio- Existing takes
but not loop-recording passes are
audible in the punch region.
So what I'm seeing is that everything is pretty much as I would expect, intuitively, except for audio loop-recording "passes" not being audible when Mute previous takes is disabled.
So if ChuckC is loop-recording audio and not hearing previous "passes", I can reproduce that behavior, but it may be working as intended.
Hope I got that all right, both in the testing and the writing.