Could be a leftover disc from drilling left inside tank. It has happened before,the disc floats in front of the opening but is too large to flow out the tank. Youroo!!
After looking into everything they said the problem was the flange to far into the tank. They still have RV they ordered new counter tops for another problem I am having forest river is replacing free. I will see when I get it back next month if toilet is fixed! Thanks for all the input everyone gave!