Piper of the swarm bug
So I made a mono black rat deck that naturally has Piper Of The Swarm for some control options when I sacrifice my rats. Problem is, when I take control of a creature with my Piper it is given summoning sickness and can't attack, which I believe is a bug in the mechanic because the creature is already on the battlefield and didn't have sickness on my opponents side of the board. It's not like I'm removing the creature from the game and getting it back, I just take control of it. So why the summoning sickness? I took over a buffed up lifelink creature to stay alive under a relentless assault, and I would've survived if not for this. Fix please?