Case standoff has is blocked

First time building a PC. I have a NZXT H6 pc case. I went to install the mobo and noticed it seemed uneven. Took out the Mobo and noticed one standoff center threads are blocked preventing a screw from going into it and may be the reason why the mobo isnt evenly flat in the case. This is how the case came. Is there a reason for this or is a defective standoff?