The bug is caused by rBb66b3f547c43e841a7d5da0ecb2c911628339f56.
From what I can see, that fix was intended to enable manual lens shift for
panorama cameras, but it appears that it also unintentionally applies
interocular shift.
This fix disables the multiview shift for panorama cameras, that way manual lens
shift still works but we get the 2.x behavior for stereoscopic renders back.
Differential Revision: https://developer.blender.org/D16950
d8e01150d6