The problem is that the surface you’re cutting up to (blue) doesn’t cover the entire sketch (orange) when projected into the sketch plane. If it were a simple surface that would be ok (extrude/revolve) but it’s a sweep, so it can’t really be extended. Since you just swept along an arc, you could have revolved it and saved yourself some grief.
The Translate From Surface doesn’t really give you the right geometry, which may or may not matter.
If you’re trying to put a groove in the bottom of the sweep, it might be easiest to just sketch it into the SKETCH_Extrude_Ac.