This is a weird one.
While using states and animation tree, I can't seem to jump and attack at the same time. I just can't figure out why.
When I use Animation Player, on the other hand, it works fine. I'm having to use both the state and the player at the same time which causes jitters in the animation.
This is the animation tree that I have:

and the code I'm using:
if is_on_floor():
if x_input == 0:
motion.x = lerp(motion.x, 0, FRICTION * delta)
if Input.is_action_just_pressed("ui_up"):
motion.y = JUMP_STRENGTH
else:
stateMachine.travel("Jump")