Originally posted by dsmithhfx Sounds more like a camera/lens issue.
I'd agree, except that it happens with multiple cameras. It's happened with the 67II, 6X7 MLU, LX, and Minolta Alpha 9. The LX and 6X7 MLU were both overhauled and the 9 has very stable shutter speeds. My suspicion is that the film is highly sensitive to any exposure flaw, so a wayward light ray that throws off a meter reading and results in an underexposure could be much more apparent than with other films.
I still don't know what Lomo film stocks are, but I've read all manner of theories from special Kodak runs to off-spec bulk buys.