As Chosker said in order to correctly occlude interiors you should use a static/stationary skylight. Moveable skylights are unshadowed which causes interiors to be fully lit (DFAO is not sufficient to overcome this problem with most scenes). Static/stationary skylights on the other hand are properly shadowed and occluded, and they also generate volumetric lightmaps or light probes which will correctly light all moveable objects within the cave area.
With moveable skylights your best option is to simply hide the area with a plane that has an emissive black material on it that fades to translucent as you get near it.
Unless you’re manually changing the exposure between areas, turning off adaptive exposure is usually a bad idea. The whole point of adaptive exposure is specifically to deal with this type of use case; Where you have two areas with drastically different lighting. If you use a fixed exposure for your whole scene then you will not be able to realistically light it.