Releasing the sprint button will no longer stop sprinting until you touch the ground

This happens to me as well. In previous versions, standing still would stop the sprint, but that does not happen in this snapshot.
Please try rewording your description and title to describe the issue better. : )

So, yea. Confirmed, I'd say.

When you pause the game by hitting the escape key, the same thing happens.

This also goes for when you're running and jumping in general. You wont stop sprinting as long as you're in the air, but the moment you land or swim, you'll be able to stop.

Yeah, when I fly in creative, as soon as I press Ctrl, I start flying like a psychopath, until I land.

Confirmed 18w09a. Was flying in a map I am working on, clicked spring (ctrl) and after I let go, it didn't stop sprinting. A little annoying, but definitely not game breaking. Would love to see fixed soon 🙂

This was still happening to me as of 1.15.2, but it looks like it's not happening anymore in the 1.16 snapshots