If you have 2.5V (2.48 is close enough) on that X terminal on the B side but Kreg is 0.6V on the same half of the board, you most likely have a miswire from the Kreg terminal to the D socket, or an ungrounded grid (D2 and D7 are the grids).
When you said before that you got "good readings" in your shunt regulator test, what were those readings exactly?
You seem to have about the same problem you had previously. It might be a good idea to go over the solder joints on the board above the D socket again.
