Solving thermal bridging.
I am building a wood frame home in southern Maine. I am using a combination of 2″ spray foam and unfaced fiberglass batt in the exterior 2×6 walls for a total of R25. Would installing 3/4″ rigid foam board insulation between the exterior 1/2″ sheathing and the cement board siding create any moisture issues in the sheating, given there is spray foam on one side and rigid foam on the other? I am concerened about thermal bridging.