Why JM1 connector signal pin 84 tied to ground on TE0715-03-30 FPGA board?

[os]

Hello.
We are using the TE0715-03-30 FPGA board on the TE0701 carrier to access an FMC card (FMCOMMS3).
Could you explain why signal pin 84 on the TE0701-05 board`s connector JB1 connected to a GND on the TE0715-03-30 FPGA board side connector (JM1)?
Thanks.

[Antti Lukats]

can you explain what you mean?

as the connectors are unisex the odd-even numbers swap module <> baseboard.

I can not see any problems related to pin 84

[os]

Thanks for the explanation!