Nothing serious at all. Internationally, anyone can pass thru the EEZ of a nation. But not thru its territory which extends to a distance of 12Nm from the coastline. India has declared its EEZ as its territory which is against the international norms.
Actually, India has requested other countries to notify the govt when they bring their ships into Indian EEZ. But the US did it without notifying, it's part of their global FONOPS.
It's almost the same with China, they want countries to take permission before entering Chinese EEZ, so the USN cross into their EEZ as part of FONOPS.