I'd be careful using full persistent desktops with appvolumes, they can cause problems, in general its a good idea to have these delete on logoff so they delete any temprary files and start in a good state. If this worked and stopped over time this may be the case. I'm doing this with physical desktops and they are a pain to manage sometimes.
The best guidlines I use is if the application installs an agent, driver, or needs specific knowledge of a specific machine its not a good appvolumes candidate. These work sometimes but can cause problems, for an example a webserver sometimes work. These require workarounds that can sometimes work,