Unable to expand a stroke in the Adobe Illustrator

There is no need to describe why we need to expand strokes, but sometimes for the tricky strokes (e.g., after using Shape Builder tool) this action does not give the expected result. It means, if I select a stroke, then use Object > Expand, I can see no changes and my selected Stroke is not able to become a Fill object.

There is an easy solution for such strokes:

First we need to select a stroke, select Object > Compound path > Release, or use “Alt Shift Ctrl 8”. Then we can use Object > Expand and that’s all. It works!