yes, it looks like either the corner design, or placement, of the toilet is problematic - even in this '16 brochure it looks as though the seat cover would not be able to be lifted up fully without hitting the wall...
contact THOR CUSTOMER SERVICE and discuss this with them - I only see that either the cover would have to be 'trimmed' back some, or the commode would have to be turned slightly(that might be a little difficult, but possible)...
by the way, I love this floorplan - we went to TX to pick up this very same type Challenger back in '14, but came home with our Palazzo DP - enjoy!