I actually think it was the right play.
If you look at where LBJ's body is it really disrupts that play. If Plumblee goes over the top, then AD dives down and he's unstoppable. Bron can also spin off Grant and come down. Nuggets don't have anyone down low to stop that at the rim, either choice and they would have been food.
Plumblee sealed off Bron so he can't get down low and still kept Grant free to stop AD if he crashed. They yelled at Jokic to come up and guard the 3 and he damn near got there.
In the end, you're up 1 and you're giving up a quick catch-and-shoot three to a 31% three-point shooter with a 7-footer's hand in his face. You definitely take that over LBJ or AD running free to the hoop.