Little Kids' Targhee IV Waterproof Hiking Boot

My kiddo wore these almost daily between 5-6 years old. They fit great and he and I were able to enjoy longer hikes because of the great support and kept his feet warm and dry. He also had outdoor camp all summer and wore them nearly day for 6 hrs a day.

Bought these in February. Today, the strap on one shoe came right off. They still look new when on and lightly used on the heel. Surprised that it just fell apart. Is that normal for the material to just disintegrate?

Thank goodness for a good warranty. Super cute boots but fell apart after two hikes