A lot of those yards were given up in garbage time against Fresno. Also, Utah's run defense is really good, so it forces offenses to throw more, which means that teams will get more passing yards, but they'll also commit more turnovers. Utah's defense has had multiple interceptions in all of their games so far except Fresno. This creates short fields for the O to work with, which means quick scores for the Utes and opposing offenses get the ball back with a long field to work with. Thus, they pick up more yards. So, while on paper the pass defense may not look that impressive, they're actually quite efficient.