Review on BIBURY Heavy Duty Utility Knife Blades SK5 Steel Standard Size 5 Portable Box(A Box Of 10 Pack）-50 Pack by Brad Schaefer

I purchased two of these utility knives and mine will not collapse fully to close.When fully closed and "clicked" the blade will fold only enough to cover the tip of the blade.This is the result for both of the knives I received.What am I doing wrong?The button is fully depressed from its fully opened position and and then proceeds to close but clicks and stops before the blade can be FULLY closed and folded. 'This makes the knife bulkier.My review is not based on a potential review of the usefulness of the knife as it appears sturdy and of good quality otherwise.