One of the chairs had a leg a little shorter than the other so i put one of those round felt protectors for wood floors and now the legs are even and it doesn’t rock anymore.  Perhaps in the packaging the leg got bent a bit! So far so good!  I had a similar model set of chairs, same material and one of them ended up unravelling and cracking.  Hard to understand and they spend all summer on a covered porch and indoors in the basement closet during the winter!  I really baby our furniture!  I’m hoping these last longer than my previous model!