The Halani Gates NPC not following

The Halani Gates NPC getting stuck behind in the map, not following to the second gate mechanism.

Bug report # 3,371,133,405

Edit: it appears the cause of this is you not killing all of the enemies at the first gate, however the gate opens before all the enemies are slain, so you end up having to run back.

The gates should not open until the NPC will be prompted to follow you if you move on.