Can you confirm is that happening because of appstack ?
Try installing the same application internally instead of assigning through appstack and check.
Also check in svservice log.
We have seen this error before and after logging of and on again the error magically disappeared. I never have been able to pinpoint Appvolumes as the root cause for the issue. I think that it has to do with the View agent but to honest that's just wild guessing..
Are you using UEM Agent? We are using UEM and enforcing Application Blocking, this is the message displayed when in use.