Isn’t such a connection affecting efficiency?
One would have to ask the designer of the board to get an authoritative answer to that question.
That said, deliberately-added gate capacitance would indeed tend to slow switching times and thereby increase switching losses, just like the resistors connected in series with the gate do. Reasons that a person might choose to do that tend to be related to reducing electrical noise and/or accommodating the presence of parasitic elements.
Since this board is aimed at applications involving relatively high voltages and unknown loads that are probably quite inductive, my guess would be that the gate network there is used to avoid dV/dt-induced turn on and/or ringing in the gate drive circuit.