I suspect you're talking about sorting, not filtering, right? Basically there are two types of sorting options: arbitrary (best match, trending) and strict (top selling, newest, higher price, etc.) We cannot know how arbitrary sorting is working and if it's working as intended, as that is black box. On the other hand, strict sorting is very clear and easy to check. It is very easy to see that none of strict sorting options works properly. From my observations only top selling sorting shows pretty much reliable results with some deviations, other options are badly broken and completely useless. CGT is well aware of that fact, yet they doesn't show slightest interest in fixing that :/