I have investigated some, and found some correlations. To recap, I have specific DSP settings and filter configured in ConvolverVST for different zones. I then use zones to switch between media sources, like music 16/44.1, music 24/96, movie 24/48 etc.
The goal is to have ConvolverVST load a different filter file for each zone.
It seems that this works as long as the network option "Use Media network to share this library and enable DLNA" is not enabled. With DLNA enabled, MC refuses to load a new filter file when switching zone. Even if I manually load the correct file and the plugin reports it as the filter file in use, it is obviously not loaded into the signal chain. I can tell because the errors appearing fits with the "old" file being used. Doing a lot of MC and Media Server restarts, and switching the plugin on and off eventually makes the new file being loaded.
I have not fully figured out if starting the Media Server also causes this problem, but it seems not. The problem is not 100% repeatable.
Not sure if this is a new or old problem, but nevertheless a bit frustrating. Is there any obvious reason for this? Can it be fixed?