Operating system: Darwin-17.4.0-x86_64-i386-64bit 64 Bits
Graphics card: AMD Radeon RX 580 OpenGL Engine ATI Technologies Inc. 4.1 ATI-1.60.26
Broken: version: 2.80 (sub 74), branch: blender2.7, commit date: 2019-06-08 13:24, hash: rB81b68f7279cd
Short description of error
edge extrusion from a pane or a Ngon creates an extra face within extruded region.
Exact steps for others to reproduce the error
Add a plane, go to edit mode, go to edge select, select edges, extrude out.
Add circle fill type ngon. go to edit mode, select edges, extrude out.
Attached file has a circle Ngon filled and a plain ready for extrusion as well as an example of an extruded plane and circle. Also note that the problem does not occur when the fill type for a circle is set to triangle fan.