Our throttling allow a slowdown variance of 40ms. With more delay, the thorttler will only lost what's more than this 40ms. So there will likely be a fast run of 40ms to catch up. (eg after cut scenes)

So the audio output have to deal with this variance: There must be 40 ms latency to not stutter without "slowdowns". After such an slowdown, there must be space for 40 ms.

So let's say on a cut scene, we're a bit too slow, 41 ms. So the throttler only lost 1 ms (this should be changed to match audio, or vise versa) but the audio interface adds 20 ms silence.
The next 40 ms will be done almost at once, so the throttler start sleeping after this 40ms and the audio queue is fulled up with 60 ms data, too much :/ (iirc there is space for 60ms, but this is a useless latency overhead / pitch shifting by the latency controller overhead)

The fix would be to also skip this 20ms in the throttler, but this would just increase the cut scene stutters (both audio + gameplay) by 20 ms.