Recently, I tested a Minecart track with an activator rail, When I take a ride on the Minecart for the first time, everything goes smoothly until I got ejected from the minecart from activator rail, When I try to ride back to the minecart, it dismounts me off even though the minecart is not on the activator rail.

 
Minecart bug video

I didn't press anything, Including the dismount key in the video.