Hi, the latest answer I got from Spitfire is from August 2023, saying the developers have been notified and will investigate the issue (it’s been the third time I’m getting told the same story so I don’t expect the issue to be investigated at all, it’s been one year lol)
Most probable thing is that the issue originates from the VST code, so it’s Steinberg’s job to do that. Many plugins exhibit the same issue (“dropouts on playback when multi-core is enabled” to name it, regardless of the trigger) so this proves it isn’t plugin-specific but global. There may be some broken code at some point when using specific VST parameters combinations. There’s no other explanation.