Hi, are you using Top-Down movement behaviour?
The reason why it’s pausing is because it checks that the S key is pressed, so it sets the animation to “walkforward”, then immediately it checks that a key is pressed, so it begins the animation “walkleft”, from the beginning frame. It goes back and forth between walkforward and walkleft everytime.
You can create a condition that checks for both keys to be pressed, or refer to this thread, where OP instead checks the direction the player is moving: