CBBS70A - 2014-01-25

All;
I am using Asterisk 1.8.15-cert3 and app_konference 2.2 on CentOS. The problem I am having is that there seems to be times when a conference user hangs up or a conference ends and yet a conference user is still listed as logged in. The real problem is that the user is still being billed for minutes they are online. Has anyone ever seen this before? The customer's conferences can get large and he is getting annoyed when he has to keep paying these bills for attendees that are still being billed for hours at a time. Its very possible that its an Asterisk issue not a conference one. Any insight at all would be greatly appreciated.
Thanks;
Frank