Geometry mesh distortion on importing

Hi i have a problem on importing a Blender geometry. Its getting distorted

My frontal window in tower and roof door entrance are getting distorted when i open file in JM it shows there are extra vertices and edges formed by them that are not existing in original file

AAh never minde,just did one from beggining … but still vould like tto know why it might happen

Was the original mesh triangular? If not, maybe it was a bug in the exporter?

I’ve not exported it .Its ablender file soo its just saved ,and each time i open it ,its fine in blender and distorted in JM