CID's aren't unassigned yes.
At some point cid 25 was created, yes. And at some point cid 25 was closed, but somehow it slipped by mIRC because now, hypothetically now since I do not know how to recreate it, /scid $cid returns /scid 25. So mIRC says /scid 25 but there is no connection 25 open.
Ok, my question was answered. "No", there is no way to refresh mIRC's connection info.
Is it a mIRC bug? I personally don't care. Logic tell's me noone is perfect, not even Khaled. :p Experience tells me not many push mIRC as I do. Experience also tells me, just as my code that works with 99% if the people, there is always that 1% that finds the little bug you (I) missed or didnt think wuold be an issue. Granted it works fine on 99% of everyones machines, if it doesn't work on 100% then there is an error in your code/foundation. It's usually something small you didn't see or hoped noone would catch. This is my experience writing scripts for the public.
Ok, can I stress again, noone is perfect? Nor are we intended to be.