Apart from removing the professional video color profiles the 13.7 update seems to have busted the CMS in AE.
This is a clean EXR in sRGB - no CMS:
This is the same EXR with project color space set to Adobe RGB and linearize workspace:
Look at the terrible banding!!!. Luckily it seems to be connected only to the viewer - rendered images don't suffer from banding, but still it used to work fine before.
After some testing the cause of this is the "Hardware Accelerate Composition" setting. If I turn it off, everything works as it should.
So yeah, Hardware Acceleration combined with color management is a DISASTER
Hardware acceleration on some graphics cards is also causing preview problems when comps are wider than 1024 pixels and you are working in 32-bit ColorSpace at full resolution. I filed a bug on that on one of my systems and then turned off hardware acceleration so I'm not saying the problem. I will check it out and file another bug report it necessary.
i was having issues with this using dpx tonight. thanks - this solved it