Timeline reverse delay when holding key

I am trying to get an actor go to another location by holding a key, and go back when releasing the key. I used a Timeline to get my actor blend from Y:0 to Y:400 in 0.5 seconds. Everything seems to work fine until i realised there was a delay before the reversing process after i have released the key. The longer i press the key, the longer the reverse process will be delayed.

I Tried to put à doOnce in front of Play but i have the same problem.

Thanks

Can you show the timeline track?

Go into the timeline track and make sure that time is set to 0.5, it is default 5.0

Thank you, i thought that by adding only two points to the graph would make it end at the second point.