It’s not particularly surprising. The F-35C is the most expensive variant, and it has no potential exports (the only operator of catapult equipped carriers are the US, the French, and the Brazilians), so it is not surprising that the navy requested a “break” from the JSF program:

OSD TOLD THE NAVY: YOU CAN’T TAKE A ‘BREAK’ FROM THE F-35C: According to a congressional source,  in its 2015 budget proposal, the Navy asked to take a three-year “break” from its production of the F-35C, its variant of the Joint Strike Fighter. Concerned this was a first step toward walking away from the program permanently, OSD told the Navy: no way.

It’s an open secret that the Navy would prefer to invest more in its F-18 fighters rather than buy the F-35C. But if the Navy pulled out of the program, the unit cost — already under scrutiny —  would go up for the Air Force and the Marine Corps.

The Navy did not get their “time out” because Office of the Secretary of Defense understood that a 3 year break constituted a cancellation of that variant, because in 3 years it will cost even more, and the DoD budgets will be under more stress.

This is, to quote Joe Biden, “A big f%$#ing deal.”