This came up in a game tonight with my Druid versus my friend's Warlock. The Warlock summoned a Vampiress into a zone with a vine marker. On the next turn, what happens if he pays the mana to make the Vampire fly?
1. Still hindered since he started his action phase as a non-flyer with a vine so even after gained flying, was still hindered.
or
2. As soon as he gains flying, becomes unhindered.
It didn't really impact the game that much but was an interesting case.