I have CMS 7.2 SP1 with MP1 and am experiencing the same issue. Reinstalling the agent does not resolve the issue. The agent works fine for about 48 hours, then the issue recurs. It also stops responding and starts throwing errors in the log about failure to install plugins as well as tasks sent to the computer time out.
Contacting our support folks to see what's up. If I find a resolution I can share I will.