Moveable meshes need to sample static lighting from the volumetric lightmap, and it stores lighting in a very sparse grid of probes, by default they’re spaced 2 meters apart. This means they’re prone to leaking lighting through walls and ceilings, and they can’t capture small lights or shadows. Also, AFAIK, they’re stored as spherical harmonics so ringing artifacts can occur.
Most likely you’re dealing with some kind of leaking, this is probably why it looks fine in some regions but not others. If you pull up the Volumetric Lightmap visualizer you might get a better idea of what’s going on.
If that’s the issue, you can try reducing the volumetric lightmap detail size in the World Settings, but the memory cost of the VLM scales cubicly so you’ll want to be careful how far you reduce it. For example going from a spacing of 2 meters to 1 meter would result in (approximately) 3x increase in GPU memory cost.
More info in the docs: Volumetric Lightmaps in Unreal Engine | Unreal Engine 5.7 Documentation | Epic Developer Community
You should also make sure your lightmass importance volume is covering that portion of the map, and that you have sufficient coverage from reflection captures (unless your materials are fully rough, in which case disregard).
Also worth noting that Static Lighting support is basically falling apart in Unreal and there have been numerous bugs with it in every version of UE5 including one where the VLM just should not build: Volumetric Lightmaps no longer work in 5.5 - #9 by fr-coder
So depending on your version and how you’re building the lighting, it could simply be a bug.