Thanks, that looks fine to me, apart from my usual gripe about having no decoupling capacitors. I would put a few on the chained power and ground lines. A 0.1uF ceramic between power and ground close to the sensors on each corner will do.
If you are measuring those voltages on the sensors then I think that is OK. So the problem would seem to be either reading that specific pin or translating that pin to the correct position on the LED matrix.
When I encounter this sort of problem I use a technique I call hit the jelly and see how it wobbles. Jelly in English means jellow in America.
That means make a change and see if the resulting behaviour exists makes sense.
So for example invert the mapping between the sensor pin and the LED position and see if the not working corner stays with the pin or moves to a new position. That narrows down where the problem is.