Seadoc,
Much like GSENT's wood block, Formula now makes a white teflon spacer block that is intended to go between the outside door, and the fridge door. It just sticks on the back of the outer door with double sided tape.
Note that since the outer door and the inner fridge door are mated, proper closure of the fridge door is highly dependent on proper adjustment of the outer door. The outer door comes out of adjustment over time from the boat banging thru waves, ect...., and occasional attention is needed to keep it in appropriate adjustment. Another way mis-adjustment occurs is by pushing down on the outside-top of the outer door while it is open. It's a natural thing to do, especially when standing back up after reaching low in the fridge. Helping oneself stand back up by pushing down on the door while it is open is a no-no though, which will without a doubt, cause the outer door to become out of adjustment. End result....an inner fridge door that does not seal correctly due to the physical connection between the inner and outer doors.
Keep the outer door properly adjusted, keep weight off of it while open, and install the Formula block mentioned above, and your troubles will be over.