J-1 and TN

I was on a J-1 visa before and I re-entered US on a TN. I have been renewing my TN by mail and have been filing I-539. The previous I-539 never asked questions about J-1 status but in the new form there is a section that asks about J-1 status and mentions having to attach all previous documents about J-1. Does this mean that my TN can be denied because of previous J-1 status? Am I better going off to the border and applying for a new TN? I guess I don't have to file I-539 at the border or do I have to? Will they also ask about my previous J-1 status if I go to the border? I would appreciate some suggestions and responses.
Thanks

You've been renewing TN-1 on I-539? I-539 is not for TN-1, that requires your employer to file I-129.

The questions about J-1 on I-539 are to do with enforcing the two-year foreign residency rule: http://www.hooyou.com/j-1/j1_2year_rule_faq.html