The refresh rate shown on the screen is indicated by the digiziter chip and is not always fully accurate. Upcoming firmware has an option to display FPGA-calculated rate which is more accurate and should be uniform (within oscillator tolerance) across units. Even if the displayed rate slightly differs, the output rate should still be same regardless of unit when using one physical console. As for why one (or is there several?) does not work with the capture card, I’m guessing it might be due to variance in those digitizer chips. I’d try tweaking sync Vth and hsync tolerance options to see if they make any difference.