Linear interpolation isn’t acting as “none” for easing.

Hi.
I have a n object that is slowly rotating 0 to 1 over 72 seconds.
i’m using linear easing because i don’t want any easing.
there’s no “none” option for easing amount for “none” .. so after a certain time at the end of the 72 seconds.. it has sped up considerably then slows back to the initial rate when the loop repeats.
i have the repeat with a number puzzle for infinity.

IS linear actually being “none” for interpolation when there’s no none choice for the interpolation easing?