Collection List only shows collected appearances, not collected appearances are not shown in the list at all. They only show up in the Detailed List/Shopping List. Please see screenshot below:

I've noticed it too, Vanilla WoW also doesn't show non-collected items anymore. So i maybe the API changed and that's the reason it doesn't work in BW either

Seems to be fixed in https://github.com/SLOKnightfall/BetterWardrobe/tree/4.5