Can' t add interface to zone

Hi! This is the second time I see this issue, on the same device. I have an 80C running 4.0 MR3 Patch 3. I' ve just created two IPsec interfaces (two tunnels), and only one of them, the later one created - can be added to a zone. Both has no referencing policies or anything like that. They' re just created. Not up/active. The last time I noticed this issue, I kept the tunnel that could not be added to a zone, and gave it a name of DUMMY_TUNNEL just so that no new tunnel would use the same ID, as it' s probably there somewhere it' s failing. Has anyone else experienced this?