Volume bar appears constantly

[ZenMatt]

When holding the phone, the volume bar appears constantly on the right side as if the volume button down is pressed constantly. It is hard to type with it constantly sliding in. What can I do to disable this annoying behavior?

[Mansi_ASUS]

Hey @ZenMatt,

When did you first notice this issue? 
Does rebooting the phone lead to the same result?

[ZenMatt]

It appeared in the last month or so when the volume down started to work again.

Restarting makes the volume down button not work and the issue seems to vanish.