Orion 2 with Tesla Model S module

Ok, I'm at a loss here. I have a project using tesla model S modules in series, connected to an Orion 2 BMS. I have set up my tesla modules with a Stealth EV cell tap board and wired my cell tap harness according to Orion's white paper on Tesla modules. Using the Orion Cell tap validation tool, the first module reads correctly for cells 1-6, with the -1 wire connected to this board. According to the white paper, the next module in series references wire -1 from the first module, and I connected cell taps 7-12 on the second module. I've checked and double checked my wiring and tested both Stealth EV boards, but the second module shows an error at cell 7 and zero voltage for the second module. I cant figure out why the validation tool shows an error on cell 7. if the batteries are in series, then cell 7 should show the next voltage in series on the tool. I've checked continuity on the cell 7 tap and its good. I've tried several modules and have the same result. any ideas??
cheers
Brian