There's a bug with the Deathslinger that makes him always have the pose of aiming. The bug happens when you simply click the aim button; it's not very rare, but it does happen sometimes. As far as...

When playing The Deathslinger there is a bug where the gun will automatically aim without using the aim button and will only go away when pressing the aim button once more.

deathslinger has no aim animation and shoots with no warning. happened multiple times.