The CLAP version of IPlugEffect doesn't inform host about changing parameter values

This problem happens with the CLAP version of IPlugEffect. Other versions (VST, VST3, AUv2) work without this problem.

I reproduce this problems as follows:

  1. I add the CLAP version of IPlugEffect to Reaper and save the Reaper project (File - Save Project).
  2. I turn the IPlugEffect’s knob and quit Reaper (REAPER - Quit Reaper on Mac or File - Quit on Windows).
    Reaper quits without any messages. If I do the same with other versions of IPlugEffect (VST, VST3, AUv2), Reaper normally shows the message “Save project test.rpp before closing?”.

This problem always happens on Mac and ‘partially’ on Windows. ‘Partially’ means that the problem happens when the plugin is added but its checkbox is not checked.

Switching to chunks doesn’t help.

How to fix this problem?

Please file an issue at github if you find a bug, bear in mind it might be a bug in e.g. Reaper: Issues · iPlug2/iPlug2 · GitHub

The same problem with FL Studio. I’ve just filed this issue on GitHub (issue 1185).