Found an very nice undocumented feature in the audio recording function. If you set IN/OUT points for the sequence, audio will record only for that interval. Useful if you just want to overwrite a specific portion of a track. Not useful if you don't realize you have set IN/OUT points and can't figure out why it is not recording as expected.
Maybe it is documented somewhere, but I couldn't figure out why I wasn't getting a recording.
This also works for recording mixer automation.
Thanks Taverino and Richard!