"Process on stop" causes CPU spike on relocate

[mks]

Does anyone knows what Reaper does upon moving the playhead with respect to processing on the Master bus (or anything requiring RT processing)? This happens even if the locate isn't moved and just clicked on again. It seems to be related to "allow processing when stopped". Disabling this makes it go away, but is obviously impossible to use in that state for most things.

There seems to be a huge RT CPU spike that happens when doing this. Made worse by the fact that if you're trying to work fast and hitting play right away, it can get into a state where it takes several seconds to recover from whatever it's doing before actually engaging play.

I recently posted what seemed like a similar behaviour. But that was related to a plugin bug with respect to adaptive processing. Though this somehow feels like it might be related.

For instance, in one session: I have RT useage hovering around %17. But relocating (while stopped) makes it jump to %50. God forbid I click two or three times in a row where it compounds and brings the whole thing down.

It feels like there is some buffer clearing/reloading or something happening to allow for the continuation of processing due "allow processing on stop". The fact that it compounds and happens when simply relocating is a little strange beyond the fact that the spike happens at all.

Any thoughts on places to look to try to optimize this? Other than disabling that functionality.