i changed the oil 2 or 3 months ago and did my usual trick of slightly over filling and letting some out and it's been fine and very level with the 2 dots on the sight glass since.
When I change my oil, I'm conservative about how much I put in. As long as it's between the bottom and the upper marks I'm happy.
I'll then ride to work and back, throw it in the garage and leave overnight on the centrestand and see where it settles. Then top it up, and repeat, one or two shots and I'll have it topped to the max (Gen1's like a full sump)
Cold oil takes forever to return to the sump. Hot oil a fraction of the time, but you still have to give it a bit of time.
Anyway that's what I do, and then forget. Rising oil level, can only be water or fuel/gasses in the oil. Or inconsistencies in checking the level (I think!)