Doh! You are right, I misread the numbers on the left of the chart The chart indicates 40 psi front, 50 rear. I will edit my posts.

I agree that riding at that relatively low pressure OP would be at increased risk of pinch flats, so it might be a good idea to go a little higher. I do not mean to advocate something that will get more flats.

90 psi is a lot higher. I cannot diagnose the problem he is having, but 37mm tires at 90 psi should be pretty impervious to pinch flats. I suspect something else is going on.