Ingles is a good shooter. But he surely needs some time to adapt to the NBA, his new team, new role and the new environment. The guy haven't spent the summer league nor the camp with the Jazz, he didn't even have much practice with the team before his first game. I just prefer to look at it from the positive angle, he offers enough of things to stay on the court most of the time despite his bad shooting percentages. His passing, steals and smart play easily justifies around 15-16 mins per game in my opinion. And the 18 mpg isn't significantly more than that, it's certainly not a major problem at all among the other things the team needs to fix at least.
He even does better defensively than I expected from him. Of course, he still looks slow(it's also partly due to his moving style which is rather relaxed) against most of the players but he plays smart on defense, he is aware of what's going on, does pretty good on most occasions and he certainly doesn't get abused by opponents.
Plus, shooters go in a slump from time to time, but they don't stay there forever, it doesn't mean they can't shoot anymore. If anything, I would like him to be more aggressive and more confident when shooting. He passes on many open shots, he's around 350th in the FGA per game list, there are many many players getting less playing time but having more shots than him.
Btw, his shooting slump is only with his long distance shooting which he has to adapt to the longer distance than the FIBA ball. Only 27% of his shots are 2P FGA and he is shooting at 62% in that department.