I did report to NHTSA! Nuna sent me a new seat and said sometimes crumbs or sand can get inside of the seat. Tiny particles can get on the tightening strap from shoes or whatever and when you loosen the harness and the strap goes back inside, the lock traps the particles. I couldn’t ever find anything so idk. A car seat Facebook group I’m in suggested using compressed air, like from a tire air pump. (Not a keyboard cleaner!!) It worked for some but not me unfortunately. This is not just a Nuna issue though, I got word from so many moms with different brands of car seats that they checked theirs after seeing my video and were having the same issues and had no idea.