I have a customer who has several exts in different hunt groups, two or three groups to one phone. All appr and ring on the phones. Every now and then some phones will be removed from certain hunt groups and it's not the same group all of the time, or the same phones. In order to fix this problem you have to go into programming and remove the phone that isn't in the group and add it back in, then it will start working again. In programming the phone still exists in the hunt group, but it won't work. The System is a MICS 5.0 XC. Any help on this matter greatly appreciated