I have incoming calls going to hunt group 200 and programmed set hunt group out of service button on reception phone. 7 days ago i upgraded software from 8.1 to 9.0.2.0 (860), this particular problem started happening after IT came in after hours and installed a UPS and rebooted the IPO. The following day this random event occured. I removed HG out of service button and reinstalled but it happened again, random incoming calls straight to HG 200 Mbox. I am gonna go to 9.0.5 tonight hoping to fix but has anyone seen this issue before?