I noticed that some of the mats in the rotary cutter and mat area of Joann's were now wrapped in plastic. Wondered if it was because of the well known, long standing problem of that smell they have. That awful smell is common in cutting mats and in my experience impossible to get out. I would return rather than waste my time trying the numerous methods - washing with all kinds of soaps and detergents, soaking is baking soda, vinegar, airing outside - I know this because I tried all of the above and more to get rid of that smell from a mat. I even left it outside on my back porch for nearly 6 months and the smell was still so bad I could not stand it. Threw it away as it was way past the return window.
Return it and Good Luck!
Here is a link to a search of this forum for "cutting mat smells"
https://www.quiltingboard.com/search...rchid=14610208