Why is move_and_slide() setting my velocity.y to 0.0 here?

[tough furnace]

if is_wall_sliding:
floor_snap_length = 0

It thinks you are grounded.

Or seperate wall slide from moving

move_and_slide()

if is_on_wall() and velocity.y > max_wall_slide_speed:
velocity.y = max_wall_slide_speed

[coral fjord]

Doing that just made it slower sliding down

[coral fjord]

This doesn't change the fact that move and slide sets the velocity.y to 0.0