The Pens had plenty of giveaways last night, and many of them were due to stupid mistakes. But I think I noticed a more systemic problem with their breakout that led to a lot of the turnovers.
(1) The pens may have adjusted their breakout so that the center came back deeper in the Pens' zone, but the wingers remained stationary and the Isles had their lanes covered. A lot of the turnovers resulted from the lack of puck support one the breakout. They had no one to pass to.
(2) Similarly, when the D did get the puck to a forward, they couldn't carry it into the zone. The forward with the puck dumped it (correctly) but the stationary wingers had no speed to chase the puck down. This led to an easy retrieval for the Isles.
(3) After retrieving the puck, the Isles could easily swing it up the opposite-side boards. The Pens defensemen, following the play, had not yet arrived at the blue line to hold the puck in. Then, they were confronted with the decision to pinch or give up the blue line. Fearing the odd-man rush created by the Isles' speed, they frequently gave up the blue line.
I also think this lack of puck support causes problems in the non-controlled-breakout setting. The wingers are just too far away from the defenseman, which forces the dman to throw the puck up the boards or try to beat someone one on one.