So, these models are counterfeit but it's hard to tell at a glance.
Having real and counterfeit side-by-side, the PCB gerbers look almost
identical down to the smallest details. There are some tiny differences
that could easily have been a rev change. The micro is different; on
the counterfeit item it is a generic Atmel 89C51 wheres the genuine
is an intel part laser marked with the Agilent/Keysight PN. And they
are clocked with different frequency crystals.
But that is about it, all other parts look to be the very same brand.
My guess is the counterfeit items came off the same production line
but they didn't have access to the OEM firmware so they had to come
up with their own. In the counterfeit unit the relay cycle counts are
always zero, so they didn't bother implementing that feature, even
though the FRAM is present on the board.