The mission starts with ''Take Warthog to Marines At Alternate Rally Point'' with the warthog that spawns with two marines standing next to it being already exploded.

Then walking through the cave, towards the shipyard there are completely static Marines. That don't change your cross hairs colour to red or green and don't react to being hurt in anyway or have any other animations.

So far no enemies have spawned yet. (don't know if this is on purpose)

Once in the shipyard there are still no Enemies, Checkpoints or Objective Change. There are more of the same static unresponsive marines however. On the other side of the shipyard there is a door in the room next to the modded tank, That when walking into will despawn everything behind you and you can see the void. the door at the end of this room refuses to open as well.

Is the mission glitched or am i taking the wrong path?