787 Heavy Mod loss of FPS when deleting ROUTE DISCONTINUITY from FP

Need some help here with this one. Using the 787 heavy mod…

Everytime I add a Departure into my flight plan from SB, I get a ROUTE DISCONTINUITY leg in the FP. When I try to delete it, my FPS drops to 4FPS. Can anyone make sense of this to me? It doesn’t matter the route I’m flying, the airport location.