Usually we have no problems "inside" our RTMM area. But with BWEP and Snow Dogs, we are sometimes outside the SAK, PNW, Pacific Fjords, etc area. You will occasionally need to disable the VECTOR elevation (if you are using Vector). Typically, and airport that needs this has an elevation problem ... usually it looks like it is in a small valley, as depicted below. When you encounter this, go to FTX Central, Settings, and Vector Elevations. Move the airport in question from "enabled" (left column) to "disabled" (right column). This will solve the elevation problem:
