This "drooping" is not a flaw. The knife is designed to have the blade in this position when fully open. Depending upon handle size and shape and blade profile, this position of blade angling down slightly can be more ergonomic for the type of cutting that blade is intended for. i.e. could be a better angle for whittling but not good for slicing.
All knife companies have some patterns in which a blade is angled when fully open. This is intentional as it puts that blade in the correct position for use. If you don't like it then most likely you do not do the type of cutting it is intended for.