Never seen that
It sounds like a defect to me. I have used a nevatear bag until recently and for a couple years of continuous use and the only damage it has taken is some smudgin on the label. And I am a heavyweight. The gym I work out at also has one that is a year old with continuous use. You should get a couple good years out of it. However, if you can't take it back you can always get a gel cover.