help- blue field wire grounded?

Hello, hoping you can help.

Fresh /6 to 360 swap. Engine starts and runs, was running well. Then it started missing/hesitating and noticed the add-on voltmeter showing excessive charging ( around 16 volts ). Checked grounds, they were at zero. Was the original voltage regulator, so I replaced it as well as the ecu (also an older unit). Added ground wires from ecu and vr housings to battery ground just to make sure. Started car, fired right up. Voltmeter shows high charge (16v), factory battery gage is normal/centered (not bypassed, still original wiring setup). Shut it down, searched threads for diagnosis help. Battery voltage is 12.43 volts (new battery). I've closed the window that had 67Dart273's voltage check info, so I can't recall what led me to this finding, but with the blue field wire disconnected at alternator and at VR, multimeter connected to blue field at alternator end I'm showing continuity if I ground the other probe for the meter. I'm assuming that should not be. It's a new M&H engine side harness, I've visually inspected and can see no damage indicating a short. Haven't run it much for fear of damaging new vr or ecu. Original alternator with 360.

I'm going to keep searching but any help would be appreciated regarding that field wire.