First thing I noticed is that Sketch1 is not constrained. Why place a circle at the origin but not have Inventor automatically constrain to the origin?
You might want to go through this document.
http://home.pct.edu/~jmather/AU2007/MA105-1L%20Mather.pdf
What if you changed the Revolve feature to 360° instead of 180°?
If that solution doesn't work (you actually want partial cylindrical feature to join hemisphere to cylinder) what if you Thicken the flat faces enough to intersect the cylinder?
-----------------------------------------------------------------------------------------
Autodesk Inventor 2019 Certified Professional
Autodesk AutoCAD 2013 Certified Professional
Certified SolidWorks Professional