POTS Miscellaneous Destination Call Forward won't disconnect

I have a Sangoma B600D analog POTS card in a FreePBX distro server 10.13.66-17. I have a Miscellaneous Destination set up (a toll-free number) through a Time Condition. When a call comes in after hours, it is routed to the toll-free number. When the caller hangs up, the channel stays open and does not disconnect. This only happens with this after hours routing, not with any local loop calls. I have 3 other PBXs using 3 different brands of POTS cards, and this method works without a problem. Any ideas?