It is a bug, but it's a viewer bug.
The correct interpretation is, "X takes a shot while Y tries to block it".
What the viewer is doing is using the incorrect text for an event which is supposed to be "X takes a shot off of a pass from Y".
That's why you will see that if this basket is scored, Y will be credited with an assist.
"I don't know half of you half as well as I should like; and I like less than half of you half as well as you deserve."