The cork roadbed I use does not have the "split" line or markings. I had the same prob on sharp curves of it "buckling" on the inside of the curves. I had to cut nothces ("V") shapes out of it to get it to sit flat. To glue it, and keep it flat, I had to tack it down on each piece (inlcuding the corners of each "V") until the glue dried, then pulled the tacks out.