Last frame of animation shows up just before the end

Hello ! I'm learning animations, and I have something weird with what I'm trying to do. I have a page corner which is used to move when the mouse is over it, stay in a "up" position, and move back to normal when the mouse exits. My state machine is like "Normal -> moving up -> staying up -> moving down -> normal". But when the animation to move down to its original position is played, the first frame of it briefly shows up in the end (the top position is showed before it stays in down position). I corrected it by putting a 0.99 exit time on that transition, but that feels like a chip trick.

Why is the first frame showing up again at the end of the animation ? (I checked, last key frame has the right image). How else can I make it so that it doesn't happen ?

Thank you !