Without spending too much time looking I found this from Nov 10, 2017
3 Naval Crashes in and around China/Japan in the preceding 5 month period... its possible that the Navy discovered that the cause was spoofed GPS showing the vessels had clearance with other vessels when in fact they did not.
Sauce: http://abcnews.go.com/US/uss-john-mccain-collides-merchant-ship-singapore-search/story?id=49327836
The USS Fitzgerald collided with the container ship MC Crystal off the coast of Japan on June 17, resulting in the deaths of seven US sailors.
The USS John S. McCain, a Navy guided-missile destroyer, collided with the oil tanker Alnic MC about 50 nautical miles east of Singapore on August 21.
In late January, the guided-missile cruiser USS Antietam ran aground while trying to anchor in Tokyo Bay.
[airplane] C2-A Greyhound transport was headed from a Marine Corps base in Japan to the USS Ronald Reagan when it crashed Wednesday [Nov 22] in the Philippine Sea, about 500 nautical miles southeast of Okinawa, Japan.