What's the deal with these guys here? Only one of each pair of agents can see the enemy, though Voxel Vision shows purple slivers visible to both. Granted, the 'invisible' slivers are smaller, and personally I've always found corners working roughly like that, with no guaranteed vision.
If you switch sides at the hole in the wall, now both agents looking in from the outside can see the MiB inside. When I tried with a Sectoid, only the fellow closest to the door (inside) could (the position opposite to the only non-spotter in the current situation).
That is, seeing an enemy round a corner doesn't seem to be particularly reliable/consistent from a player POV.
XCF 3.2 snapshot, OXCE 7.9.16.
The original report that led to this is
here.