I did not use a catalog - i have no idea how to use it with many hard-drives and 2 or 3 PCs i have. So i prefer Sessions.
Of course, all needed things is stored inside .cosessiondb file but even with proper editor (HEX?) it looks extremely awkward to solve this issue
(i have it at least at 3 PCs, C1 v10 and v11).
So, i consider its a bug, maybe hard to reproduce, but needed to be fixed (like a excessive cropping after Distortion correction and few others, remaining for many versions - pity for such great software).