The Hawks are better than most overall given that they're among the best possession teams in the league, but overall the defensive zone turnovers happens a fair bit, particularly in the playoffs. Hockey by its very nature just isn't a very clean game, it can often be pretty sloppy and it's sometimes hard to do basic things like passing the puck around.
It's been a bit more common the last couple games though, protecting a lead can be tough and cause you to sit back which ends up causing more turnovers.