Weird hole from correct Dem

When creating a mesh file from from what seems to be a correct DEM file ,a specific area in the scenery contains weirdly a 'hole' where a slopping mountain side is suppose to exist. The following pictures demonstrate the issue.SIM RESULT 1 and 2 show screenshots in FSX of how that mountain side is missing a semicircular chunk. Picture named 'dam hill' is a picture of the place in real life and the area missing in FSX is the part in shade from the top left part of the mountain.Picture 'GE TOPDOWN'' is from google earth for a top down perspective.Now the following picture named 'MICRODEM TOPDOWN' is a screenshot from MicroDEM software with the DEM file at that location . You can more or less see that the DEM file is correct with a gently negatively elevating gradient on the north side of the crest , just as in reality. Also the window on the right side shows the elevation points just aft and forward of the crest corresponding to what exists in reality.So is there an axplanation for this and how can i fix this if possible?