Hi,
I have not been aware of this, but as I am imagining the situation it is as follows:
1. 7zip decompresses the files and starts a shell copying process,
2. The shell copy process is intercepted by CH,
3. CH stores the reported file(s) as a task and returns control to the calling app (7zip).
4. 7zip seeing that shell has already finished copying (shell normally is being blocked until the operation completes) - deletes the temporary folder.
As far as I see - currently the only way to solve these kind of problems would be to disable temporarily the shell integration (for the time of dragging from 7zip).
I have added this as a low-priority task to my todo list (there are other, much more grave problems with ch

).
Hope the workaround will work for you now.
Regards,
Ixen