It seems like many, if not most, of those shots are wide open. Jazz aren't really jacking a three early in the shot clock. If the scheme holds, our percentages shouldn't drop too much.
Additionally, young players that add a lot to their game traditionally struggle earlier in the season (see Hayward, Gordon.) It is one thing to add new moves. It is another thing to polish them against true NBA defense. Lyle swill come around, especially as the starter and bench roles become more stable.
I fully expect Lyles to be in the mid to upper thirties by the end of the season. There's just no way that Johnson stays at 54%. He'll come down at least to 45%, which is unbelievable shooting. Hood will come down as well from 48%. Will Exum stay at 43%? Ingles could get better, and so could Lyles. What will Hayward shoot from three? As you've said, the shots are open, so I fully expect us to be in the top throughout the year.