No. At first the game told me that my landorus was jolly and later it turned into serious nature instead. The best proof I have of this is that the IVs are identical in both pictures. Very unlikely two different pokemon.
What's your Player name (IGN)? AvatarAsh
Number of hours played? 1020
What's your favourite Pokemon? Absol
What country are you from? USA
How old are you? 22
Which server do you play on? Silver
In a PVP match, I used roost on a togekiss. The opposing bisharp outsped and died from life orb damage, but then togekiss did nothing when it should have roosted.