I have a moving platform that is scripted using the built in platformmover script built in to unity. My character jumps through the bottom of the platform. How can I stop this from happening
First, colliders doesn’t push character controller. Only rigidbodies(non kinematic) are pushed by colliders. But I asume you want still using the character controller. The best way to achieve is to parent the player to the platform.
The platform must have a collider and a Trigger(offset y axis). When the player enter to the trigger, parent the player to the platform this parenting will allow inherit the translational movement from the platform to the player. When the player exit the trigger you should disable the hierarchy making the player.transform.parent = null.