Temporary polyline does not go away

[andrerav]

Expectation: If I close the Profile Tool panel, the temporary polyline should be hidden
Actual: The temporary polyline stays on the canvas until the end of the universe

[nicogodet]

It's an issue I'm aware of.
Unfortunately I will not fix it in short term.

[robbitt]

I'm having the same problem - a temporary polyline and its red points persists at times.