Gen6 Battle Factory is apparently having some Gen7 mechanics today...? I play Factory a lot and never witnessed this before.
Relevant replay:
http://replay.pokemonshowdown.com/gen6battlefactory-610216156
Relevant turns:
Turn 35: Metagross mega evolves on this turn and immediatly outspeeds Mega Diancie, which had already mega evolved previously. Per Gen6 mechanics, Diancie should be faster, as Metagross would still use the pre-Mega speed. Metagross going faster, however, IS accurate in Gen7 mechanics, as my Diancie had HP Fire (so it had 349 speed vs Metagross' 350 Speed)
Turn 58: Scarf Heatran uses Stone Edge before Talonflame Roosts. To my best knowledge, every single Talonflame moveset in Battle Factory has Gale Wings, so Roost should go first. However, this is also accurate on Gen7 mechanics as Talonflame wasn't at full health on this turn.