How to hang up SIP channels without channel ID?

When I do a “sip show channels” on the CLI, I get an entry like this at the bottom of the list:

This channel has been there for several hours.
When I do a “sip show channel 78cbf6107d1” on the cli, I get the channel information, but the field “Owner channel ID” is empty. This is bad because without a channel ID I can’t soft hangup the channel.

My two questions are:
[li] How can I remove this channel?[/li]
[li] Why does the channel exist in the first place, is there anything I can do to assure that channels are closed correctly? [/li][/ul]
We get 2-7 channels per month that are shown at the bottom of the channel list but their peers are no longer active. Any ideas why and how to avoid this phenomenon?

That behaviour is buggy. Which verision of Asterisk are you using?

I’m using Asterisk 1.4.24 (64 bit build) on a SuSe distro.

That’s nearly 11 months old. There is a good chance that it has been fixed.