How soon after you've steamed the milk do you pour??
The thing with skinny or semi-skinny milk is that the foam likes to separate from the bulk of the milk fairly quickly, which leads to what you described.
Be sure to constantly "swirl"/"swish" the stretched milk in the jug until you pour (i.e. as soon as it's steamed, make small circles with your milk jug in hand).
Having said that, it's hard to say for sure what's going on with seeing you in action. If you post a video up, we could certainly diagnose most things further.
Hope this helps.