SIP channels perpetually in use

Hi there, I will probably fix this with a restart of asterisk, but was wondering if this is a known bug.
Asterisk 1.6.2.11 built by root @ distro-e5.asterroid.com

If it matters, thirdlane version is 6.1.1.12

I have two channels that are always in use. I was made aware of this when I had weighted call queue that would only ring lines 3 and 4. It bears mentioning that the two problematic extensions 1 and 2 are on the same Linksys SPA2102 ATA. The inuse status persists after disconnecting offending ATA and reloading sip. Furthermore, post sip reload, asterisk still shows the channels active via the old IP that is no longer in use.

I "fixed" this for the customer on the fly by logging into ATA and configuring two new extensions to be their local extension 1 and 2. Weighted call queue is working as intended now.

Once again, I'm guessing that restarting asterisk will fix this, but wanted to know if this was something that had a quantifiable reason for occurring.