AM3352: tCK out of SPEC for DDR testing

Hi Expert

My customer has a issue of tCK out of SPEC for DDR testing on customer's board.

The tCK test result they got is 2.495 ns, but the Low Limit of SPEC is 2.5~3.3ns.
He refer the link:

https://e2e.ti.com/support/processors-group/processors/f/processors-forum/482267/am335x-ddr-pll-tolerance

but the test result is still fail

Could you help me to solve it?

Thanks

Daniel