Looks like a couple hours after we enabled this plugin our CPU load (by Stash JVM) started creeping up, eventually getting to about load-average of 30. This didn't appear to cause any issues other than slight slowness in Stash.
Disabling plugin instantly decreases amount of CPU used by Stash and system load drops rapidly.
Our instance is relatively small (dozens of repos, dozens of users, maybe one pull request per hour?). I don't have too much freedom to debug things on a running system, but let me know what would be helpful. I did not see anything obvious in log files, but I can enabled JMX over the weekend and take a look there.
This is Stash 2.10.0 and plugin 1.2.2