In short, it still leaves much to be desired in NBA 2K17. Apparently, this is a "bad block attempt":
https://www.youtube.com/watch?v=pdpI5ViC37s
From the looks of it, because Valor managed to get the chase down block, my attempt was considered redundant and therefore bad...even though I managed to get back, alter the shot, and not commit the foul. There's also the issue of sometimes getting hit with a "lose ball" deduction when you're fouled, the foul being the reason for losing control of the ball in the first place. The whole system feels very antiquated at this point, still skewed towards punishing than rewarding or fairly assessing, and not taking into account the overall performance. You can play a brilliant game for three quarters, and then drop two grades due to a couple of errors early on in the fourth quarter where you're up by 30.
I recently went back and played a bit of NBA 2K15 to get some screenshots for the character pages in the Wiki, and I have to admit that the grading system has improved a little since then. However, it still feels "last gen", with a lot of legacy issues and logic that almost seems like it's designed to make it harder to earn VC.