Halo Infinite - LASO glitches?

The issue you mentioned at first is due to the Cowbell skull and its increased object displacement. I'm guessing this issue occurs after you use the Scorpion cannon to clear Outpost Tremonius? It can also happen with a Rocket launcher but not with many other weapons. What's happening is you've launched an enemy into orbit but that enemy is still alive somewhere far away. If this happens for example during The Sequence, you can simply fly out of the area and back and it'll usually open the door. Not flying too far, though as that can reset the enemies.

On outpost Tremonius you'll just have to restart the mission.

I've never heard of- or experienced your issue with the threat sensor, though.