The defense has not been good enough no doubt, execution, rotations and all that BUT I think it also coming from the offense.
What I mean is (this happens even when the Jazz win just less so) the Jazz' offense will go multiple possessions in a row of negative plays. I can't be the only one that notices the Jazz will turn it over (usually a stupidly) leading to a layup and if they don't immediately turn it over again they have a missed layup or missed wide open 3 which leads to another layup/dunk or 3 for the other team. On the rare occasion the opposing team doesn't hit this open 3 they get the offensive rebound and score anyway.
The Jazz will have a combination of these happen on multiple possessions in a row and not just once but multiple times during the game. They will have these negative plays 2, 3 or sometimes 4 consecutive possessions in a row AND multiple times.
I can't say I've remember or have ever seen that before, a team so consistently have so many consecutive negative plays.