I designed the "dash" to move to max 64px. But it can teleport the character more.
Are you saying that your issue is that it travels more than the max 64px?
One probable reason is that while colliding with the solid wall construct tries to resolve the collisions and it gets pushed up and starts sliding until it reaches the top of that wall.
If that is the case, one idea is that you could try to stop the dash when colliding with the wall by stopping the tween.
If that doesn't help it may be a good idea to create a small demo with your issue and share it here so someone else can have a look and help you.