Why? What are they doing differently once they get the lead? I always appreciate your insight into the X’s and O’s and would like to see what you’re seeing in their play that causes them to change lay bad with a lead?
A lot of times it's a simple mindset where players don't want to be the one that makes a mistake so they let off just a bit and the other team is able to take advantage of a lower amount of pressure. A defensmen loosening up his gap in the neutral zone to be "safe" would be an example but unfortunately that may be exactly the space he needs to make a play and beat the defender.
There are some players that coast because, well, because they're lazy and don't pay as much attention to defending with the lead.
There's also an element of panic that creeps in, it kinda goes with being safe but not completely. It happens a lot to the forwards, the D will win a puck, move it up to the forwards but they'll panic and not make a good play. Sometimes it's over stick handling and doing to much and sometimes it's not realizing they have time and just throw the puck somewhere they think is "safe" but ultimately give away possession.
Fans will cheer when the puck is cleared during a long Dzone possession and Willy will act happy that a forward finally got a puck over the blueline but too often it isn't a quality clear that turns into a good forecheck let alone offensive pressure. Something like a forward after failing to clear the puck a couple times will get another touch and just lofts the puck up hi in the air out to the Nzone which is great to maybe get a change but it doesn't help the flow of the game.
Granlund is notoriously bad with this sort of thing, his hustle is why a coach puts him out there a lot in those situations but his puck decisions can be mind boggling.
Some teams 100% go into a passive trap and strangle the life out of the game when they have a lead, we saw the coyotes do that Monday but Nashville doesn't. You hear the coaches and player talk about "keeping their foot on the gas" or whatever analogy about doing what was successful all game and not turtling.
We usually see a mixture of all three things bite the Preds when they get crushed during a 3rd period lead.