Keynote bug: re-record bug tested on display computers at the Apple Store

My 2023 mac with an M2 chip, running Sequoia 15.5 with Keynote 14.4. can record audio narration for a Keynote presentation correctly if I could record the whole thing mistake-free in one go, but I never can. When I need to re-record from a mistake partway through the presentation, it fails in one of two ways: either it quits at the point from which I re-recorded, or it blasts static noise from the point at which I re-recorded. I tried re-installing my operating system, re-installing Keynote, and using several different audio input devices. These failure modes occur whether I use Play Recorded Slideshow, or Play/record slideshow, or Export to Movie.

Tonight I went up to the Apple Store with an appointment with a tech. Before the tech got to me, on each of the 3 Mac Mini's on display, each an M4 running Sequoia 15.5 with Keynote 14.4, all with internal microphones, I created 3-slide test Keynote presentations, and re-recorded from the middle of the second slide using Play/record slideshow, recording, exiting, doing play/record slideshow again, dragging the slider to the middle of slide 2, and re-recording from that point. On two of the computers on display, when I clicked Play Recorded Slideshow, it blasted loud static when it got to the re-record point, making nearby customers jump. On the other computer on display, it just quit at the re-record point in the middle of Slide 2. These were the same two failure modes observed on my Mac, which I had brought to the store in my backpack for repair, but brought back home because the problem is clearly a bug.

The techs at the Apple Store have no channel of communication with Apple's tech support, and certainly not with engineering. There was nothing they could do to help except suggest I submit feedback.

My current workaround is to record Keynote presentations on a 2013 Mac Mini with an Intel chip running Catalina and Keynote 11.1. It works, but my old computer is marginally functional. I just tried my little test on someone else's MacBook Pro M1 using internal speakers, Sequoia 15.5 with Keynote 14.4, and re-recording from the middle actually worked there. I don't know if it would work on a MacBook currently for sale -- I wasn't able to try one at the store tonight, 6/24/25.

Does anybody have any good workarounds? Does anybody at Apple know when a patch will come out? I'm working hard to prepare a course for the fall, and not sure now how to proceed. I really like Keynote when it actually works.