I have several cropped views of a section views, have been using this method for months, and suddenly one out of multiple cropped views disappears every time the crop is applied.  I have tried deleting the sketch and using a different one (for lack of any other idea as to what is wrong.)  Any other suggestions as to what to try or what could be going wrong?  I'm using 2015 SP1.1 and have been for 2 or 3 months with no other issues with cropped views.