sometimes it isn't the mat, it is the worn blade in the cutter that causes the problems
I bought the largest green mat about 20 years ago, because I had a cutting table to fit it. Much of that acreage is wasted space. 36" on the longest side is more than enough for me, I can't cut steadily at that distance anyway and that is the longest ruler I have. I do far better precision cutting with the fabric folded in half which is more in the 20" range and cutting goes much faster.
What I've ended up doing is sliding the sides around because the space I've been cutting on is worn, looking for a new clear space. I've got two more moves then it is out of here and I'll never buy one that big again. I'd prefer smaller and replace them when needed. Our differences are what make us interesting, right?