Lightroom edit, preview, and output do not match in brightness

[use3982stock]

I have a fully colour managed work flow. Everything has been working fine for years.

I have a new set of photographs that are in studio, plain background, dark, of few colours. It's a Harley Quinn red and black traditional outfit shoot.

I have 4 shots that are very similar with only slight variations in poses.

In develop, they all are similar, face brightness values at 80%.

Press n and now 3 of them look slightly brighter .

Press g and they're a little darker. 

Export to srgb jpg. 1 looks similar though not identical to develop module. 2 look brighter, as if it was a high key shoot. The last one looks blown out and the face looks completely white.

So far, other images in the set seem OK. I've edited 10 others.

This has never happened with other sets. 

Obviously I can't post the photos in public . But there's no way to report bugs or get support. 

[cmgap]

You can  report bugs here: https://feedback.photoshop.com/photoshop_family/?red=a

Can you crop the images to show what  you are describing?

[use3982stock]

I'm confused, wat's the difference between https://community.adobe.com/ and https://feedback.photoshop.com/

but they're all volunteer forums with no real staff right?

Here's the crops of one. All 4 shots are the same, except for hand position and face. So overall the colors/light are similar.

[cmgap]

The official name is Photoshop Lightroom  so feedback is funneled through that portal. It is attended by the PS/Lr product dev team. Can you add your attachments via the post editor? I am not able to see your images.

[use3982stock]

Yes it deleted all the images somehow.

I attached to the main question up top.

[TheDigitalDog]

 First, try disabling GPU in the preferences (Preformance). Any better?
If not, recalibrate and build a new ICC profile, the old one might be corrupted.
If you are using software/hardware for this task, be sure the software is set to build a matrix not LUT profile, Version 2 not Version 4 profile.

Always compare in Develop module, not any other modules at 1:1 as it uses a different preview architecture for close visual inspection of the data. 

[use3982stock]

Turned off GPU, no difference.

My ICC is auto generated periodically by Eizo software. Do I need to do anything?

Also note it's only these few photos that have no human skin color that went crazy in different ways.

Other stuff seem fine.

[TheDigitalDog]

Make sure the software is creating V2 ICC profiles and Matrix. Probably a pref.
You should always test output using good color reference images designed for that task. The color reference images RGB values are such they are set for output and are editing and display agnostic. Test the output this way and examine for the same color issues so we know it's not your image specific issues causing the problems such as:

http://www.digitaldog.net/files/2014PrinterTestFileFlat.tif.zip

[use3982stock]

It's fine for everything else. I just did a headshot, every single module
looks consistent, as does the jpg.
It's only these 4 photos, and even within these 4 they are inconsistent
even though there's only small head tilt and arm position changes.

The ICC says tone curve LUT
I can't see other info or ways to change the ICC.
ᐧ