Plugin set_parameter not taking effect immediately?

[mgrachten]

I'm using a Pianoteq as a dawdreamer plugin to render MIDI files. I'm changing some plugin parameters to vary the sound. I've noticed that at least some parameters take some (wall clock) time to come into effect. When I render immediately after setting the parameter, there is a fast transition at the beginning of the sound, which is not there when I time.sleep(1) between setting the parameter and calling render.

Below are two sound examples to illustrate the issue. In both examples I've set "Lid position" parameter to 0 (from the default 1), which causes a more muted piano sound. In the example without the sleep, you hear that the first notes are brighter/louder, and then very quickly the sound becomes muted, as intended.

If this slow transition is expected behavior, is there any way from dawdreamer to control it (i.e. choose whether the parameter change takes effect immediately or with a "fade in"). Or is this an internal issue of the plugin?

Thanks for any help or insights!

without_sleep.mp4

with_sleep.mp4