Ok, so I spent some time trying to narrow down the issue. The problem seems to be located in my processor’s process() method (see code in a previous comment).
I replaced my audio engine processing code with a basic sine wave generator. With this simple code, everything runs well, all parameter updates (sent from performEdit) seem to arrive properly in the inputParameterChanges queue.
Now, if I make a sleep() call for 5ms after the sinewave generation, the problem occurs very frequently.
Could the inputParameterChanges queue feeding be blocked when the process() method is doing too much work ?
Any idea on what could be the issue otherwise ?