ArcGIS Pro crashes with serious application error when exporting a layout that contains an empty map frame is inserted by clicking Insert>Map Frame>Other and selecting the blank map frame labeled <None>.
Instead of using Insert>Map Frame>Other and selecting the blank map frame labeled <None> to create an empty map frame, add a new map to the project. Remove the basemap so that the new map contains no data. On the Insert tab > Map Frame select the map frame for the new map. This will add an empty map frame that will not cause a crash upon layout export.