I was working on a breezehome basemant. When testing it with my level 60 character there was no problem.. When I made a new character and either COC'd to the location or entered it through a door things got strange. The room started out dark and the lights slowly appeared, my character was pretty much immobile until the lights finished displaying, combat music was on and depending if the DLC's were activated I got either 3 mammoths or netches half in the basemant and half imbedded in the ceiling always in the same area right near the entrance.

Someone suggested deleting the navmesh and all markers. I tried that but didn't help.

Finally I made a new cell, copied everything in the first cell and pasted it into the new one. That fixed it but where in the heck were those mammoths and netches coming from? I've heard of basemants infested with rats but mammoths are a bit much. My cat occasionaly runs over my keyboard while working, could she have done it?

The lights and being immobile could be a loading glitch, the combat music is a glitch I've had quite a few times in the game, unless you set the location to have that music. The mammoths, lolwut.

Did you duplicate the glitchy cell, or did you build it from scratch?

I copied the entire contents on the cell. It would have taken forever to rebuild. It sort of grew uncontrollably from a basemant into an entire stronghold.

I find it is best to have a test save that is made with no mods at all on the game. This will eliminate any issues from other mods affecting a new mod or a new mod mix.

You can always use the console to buff up this character if you have to test higher level content. However, never save over this save slot, make a new one if you have to save for some reason.