On my 2007 I got a low oil warning light once at a stop sign, pointing downhill on a slope. On the oil cooled bikes the oil level sensor is at the back of the sump.
This happened to me after my first oil change on my 2012, where I tried to nail the middle of the sight glass. I just put another 1/4 quart of oil in, which got the oil to nearly the top of the sight glass. I have not had a repeat occurrence since.I get a “check engine oil level” warning on the TFT display. Pull over, shut off the bike and check sight glass - oil is middle of the red circle.
I don't seem to have that problem with my 2018 GS. They say it holds 4 litres and that's what I put in to get to the top part of the red circle. I do tilt the bike to the left and right to try to get all the old oil out better. I started doing that when I noticed when the valves are checked It's missing a half a quart.If you overfill the WC bikes you will get clutch drag and the shifting will get notchy. The extra oil will add some rotational drag/resistance to clutch basket spinning and it made my 2014 GSA shift poorly.