Is it possible that the first time you checked it, it was on the sidestand so you could not see any oil in the sight glass. Then after adding one quart of oil, you checked it with the bike upright, and now being one quart overfull, it would not show up on the oil sightglass because it would actually be overfull?????
The sure way to verify what you have now is to drain the oil and measure it. You can assume that some (1/2 to one quart) will remain in the oil filter, but what comes out should be about 3 quarts, more or less. If it is closer to one quart, there was no oil in it before you put it in. If the drained oil is closer to 4 or more quarts, then the scenario I questioned at first may be the answer.
