The New York Islanders have salary-cap overages that impact their cap space heading into the summer.

Per PuckPedia, the Islanders' bonus overage carryover is $3.5 million. 

Here's how they get to that number:

"The New York Islanders super rookie Matthew Schaefer earned the maximum bonuses possible for an Entry Level player - $3,500,000.  He hit 4 “A” bonuses for Goals, Assists, Points per game, and Time on Ice, earning $1 million, and by finishing in the top 10 among NHL Defensemen in goals, he earned his $2.5 million “B” bonus.  Since the Islanders used LTIR and finished over the cap, this entire $3.5 million bonus is an overage.  This large overage isn’t quite as high as the overages incurred by Boston ($4.5 million in 23-24) and Edmonton ($3.55 million in 24-25) in recent years."

Schaefer earned every dollar of his bonus. It's not a problem, just something the Islanders need to get used to. 

To sum things up, this means that the Islanders' cap hit next season is reduced by $3.5 million.