In thinking about this a bit more I remember way way back when I was first wanting to make sense of fluid.ampslice~ that there was something about the envelope followers getting pulled towards -INF with synthetic signals so normal-ish thresholds would take a really long time to respond. I don’t know what change was made but it was eventually addressed in a fluid.ampslice~ update and I’ve been using it since. Perhaps this wasn’t ported over to the offline .buf version?
This would make sense since when analyzing the whole buffer that it would behave reasonably, but when doing isolated bits it doesn’t have enough time to respond. This would also explain why the first onset is being missed in jongly when analyzing the whole buffer.