Well, I said I would say no more, but I just find this fascinating.

I put pictures of the actual valve you have shown in the second figure, a couple of years ago here in this forum. Can't find them now, but this is the same subject.

Look at the piston that actuates the light, move to the right, it cuts off the input to the back brakes. To the left, cuts off input to the front. But, when it does cut the flow off, the pedal can still be pushed to actuate the "other" end of the system.

Again, we need someone without a valve to open a bleeder and tell us what happens.

I am really sure about what will happen, and if we could post that result here, actual data, we can all positively learn, eh?