Free Shipping issue w/ Google Product Feed

I have 9 products labeled as “free shipping” out of 600 total products.

These 9 products have never been approved by the Google product feed, and it must have something to do with me labeling them as “free shipping”. Every single other product has had no problem whatsoever getting into Google shopping.

Are there some changes I need to make to my product feed export so that Free Shipping comes into Google as a valid entry?

Thanks for your help.