I did some searching, but cannot find any means to report a site bug. I assume creating a new thread here will have to suffice.
When using Advanced Item Search, it appears as if the Augmentation Type filter "Type 20" is not functioning as expected. As an example, I set Class to Beastlord, Slot to Primary, Augmentation Type to Slot 20, and clicked the Augmentions only radio button. Results returned seem to include any and all Augmentation Types.