What was the weather like? This can be normal. Cold outside, bike stored inside? What was the weather like when you changed the oil? It could just be a little but of moisture in the engine. I'd start it up and let it warm up for at least five minutes, let it rest and see if it looks different. If it looks the same, or more foam, change the oil again.
That's what I'd do.
That's what I'd do.
