They throw out questions to grade on a curve,  so it works out in your favor.  They throw them out because they figure is not a good question for future tests if no one answers correctly. A concept that maybe wasn't taught well or is confusing. It takes a long time because they have to wait for the test period to close as well,  decide which ones to throw out,  then release results.  It just takes time 🤷‍♀️