That's kind of what happens to denim when you air dry it. They are fine. Wear them a bit and you won't notice. If it bothers you next time tumble dry them on low.
Having recently compared one tumble dryer to another, “low” covers an exceedingly wide range, from genuinely lukewarm to “damage my clothing please”. Oddly, both machines I compared were LG and were not especially old. “Low” is a relative term.
Yeah, I like that about new denim. After 6 months of wear it won’t do that so much and you’ll miss it. Maybe the poster is used to denims that are not 100% cotton.
