So… I was getting tiny dropouts in offline renders. Eventually I noticed that Nuendo was dropping into record (well, trying to, no tracks were enabled) in normal playback of the project at the point where the dropout occurred in the render.
It turned out that the cycle start locator was at that point, of course, and that I had accidentally hit the “I” key. Turning record drop-in off solved the problem.
But this begs the question: why does Nuendo try to drop into record during an offline render? Especially when it causes a dropout.
(12.0.52, Mac Studio M1 Ultra, Monterey)