Takedown missing flooring on some walkways - npc's can get stuck

The ground portion of Takedown is missing the flooring grating on some elevated walkways. I lost one BOFF stuck in the underlayer when I encountered the first bad area. After that I was able to hold officers on one side and bring them across one by one to get the other three to the final fight with Gaul.

Then after defeating Gaul the mission didn't end. On the map I could see 4 Vaadwuar soldiers in the sloped ramp leading down from the observer area to the main battlefield. I couldn't get through the door to fight them because the "Defeat Gaul" mission objective wasn't complete. If I had to guess I'd say the flooring on that ramp was missing and they didn't make it down and out the door before it closed. Needless to say I had to abort the mission and no doubt I'll have to re-do the entire ground portion of the mission if not the entire thing. Something I'm not going to do until I'm assured the bug is fixed.