Issue #28904: CambridgeMassChemical01: Previs and Precombine Issues
This cell has quite a few issues with the precombine, in part because it appears to have been designed as an exterior and then ported to be an interior cell instead. Two notable issues in the cell are that the machine in the center (REFR 001C7EE0) breaks the occlusion culling. Looking through the gap in the machine toward the far wall allows players to see significant chunks of the void as parts of the precombine are being hidden, either by a room boundary or the previs system.
The other issue with the cell is that two objects used in several locations, MetalTopA1x1CorLFull01 and MetalTopA1x1CorRFull01, have malformed meshes with a gap that has been baked into the precombine. In most of the cell that gap isn't obvious, though it has led to locations where viewing the horizontal metal beam from above (such as jumping while next to the upper catwalk door) leads to a black bar becoming visible. (Said bar being the top of the metal beam)
Screenshots of both issues attached for reference.