a) The aircraft has two engines, but the trails are three: two wakes come from an engine, one from the other one.
b) When the trails melt, you can see that they change in three different ways, showing three dissimilar sprays and substances.
These observations show these contradictions:
1) Because there are three trails and two engines, debunkers try to explain this anomaly, asserting that it's an optical illusion.
2) About different way of melting, debunkers state that it happens because of different engines and for the atmosphere is not homogenous.
3) The final part of "metamorphosis" shows three trails. For all these reasons, the more debunkers try to demonstrate that chemtrails are a hoax, the more they must deceive people with ridiculous and contradictory statements.