Their code for the condition checkbox filtering is a little messed up. They have "Other / Unspecified" in the checkbox filter options, but that option seems to be no longer available when posting a new ad, so maybe they modified the code in one place to remove it, but didn't in another and it jacked things up?
What works for me:
- Select the condition box you want - Then select the one above it too - This will return results for just the one you want
This does not work though for the "Other / Unspecified" checkbox (since there's no box above it), or if the checkbox directly above the one you want is non-selectable.