I had this problem a while back.

I think I at some point tugged too hard at the sides when applying the front lace and stretched the lace differentially (ie more at the front than at the back), so that my front lace section was slightly funnel-shaped and could never lie flat. I experimented with some more controlled tugging to even the stretch out, but it was never wholly satisfactory, and I ended up ditching the piece.

Could it be this in your case? Can you post a pic?