I am aware of the issue. Unfortunately, I didn't see until after the lecture yesterday an email that came through warning:

Teaching spaces are currently undergoing some sound issues that AV are aware of and working on. In the meantime, if you are experiencing any technical difficulties, it’s been suggested that you use the “lecturn mic” and stand in the same spot when talking.

I used the pack mic, which appears to have worked in the room, but not for the Echo recording past the first few minutes.

I am planning (barring the unforeseen) to repeat lectures 0 and 1 after lecture 2 today to get an Echo recording of them. I also intend to run a backup audio recording in case the issue is still not resolved.