Both Group at 0% and Group at 100% are allowing any level of damage, including fully repaired through filters when the filter is set for undamaged items only. Neither setting allows only fully repaired items.

Group at 25% seems to work as expected, allowing only items within 25% of the damage value assigned in the filter.

I'm using 4.3.5 b30 because it's the latest recommended build. If this has been fixed in the two unstable builds I don't see it here in the issues or in the change log anywhere.

Algorithm checks if item in filter and actual item in world are both a part of the same damage group, with the lower and upper groups split at the percentile. Of course, this check is only performed if the match meta option is turned on. This option is disabled at zero, at 100 both items are generally in the lower group unless one is perfect while the other is not.

Which still results in the BUG that you can't filter off undamaged items from damaged items.

Undamaged tool in filter with 100% setting is except only fully repaired.
Though, I can refine this a little bit. Will change it up to work like AE's

Fixed via 52864ac