Rotation over 360.

So Im trying to make a gameobject rotate smoothly over time. When pressing space it rotates 100 degrees, but when it tries to rotate from 300 to 400 its rotation gets set to 320, these numbers are from the ToAngleAxis method, the euler angles are different, so on the last move the 320 are -40 euler.

So my question is what is causing this and how can I fix it. Also if I set the first step to be more than 360, it will rotate fine, but on the second rotation it does not rotates fine.

Here is a gif that shows the rotations: https://cl.ly/2a2p2e0G1r0H

The code for rotation is from here but modified so it does not rotates in random directions.