Recently I cast Gust of Wind to push back a group of chitine that suddenly jumped the party. It worked surprisingly well but just to be safe, I wanted to place my wizard behind a statue to stay out of their reach in any case, while the wind supported my allies.
The DM asked me how the position of the line works when I move away from the original casting position. I don't know, I said, so I quickly looked it up but it didn't get more clear. He ruled that the blast of wind continued blowing from where I originally cast it, regardless of my wizard's new position (which is how I intended it).
Now after the session, reading the spell description still doesn't clarify it to me. Is there something I'm missing here?
A strong wind 60 feet long and 10 feet wide blasts from you in a direction you choose. Each creature that starts its turn in the line must pass a strength save or be pushed 15 feet away in the line's direction. […]
As a bonus action, you can change the line's direction.
What is supposed to happen to the position of the line when the caster moves while the spell is still active?