Why do colors in Photoshop look different from Lightroom?

Question

I know there's plenty of questions like this and I've tried all the provided solutions, but I think my issue is slightly deeper than that.

I have noticed that when I do an external edit from Lightroom to Photoshop the colors in Photoshop appear to look drastically different from what I see in Lightroom. This is only noticeable on black and white photographs (I work on old B&W paper photos with different shades of colors).

(The top one is photoshop which gives some greenish tint to a photo, the bottom one is Lightroom which is correct color. It may not be very noticeable here because of the white background around, but in Photoshop the color difference is quite apparent.)

I have made sure that my Lightroom's external editing color space is set to "ProPhoto RGB" and my Photoshop color settings are set to "Preserve Embedded Profiles". I have also calibrated my monitor with DisplayCal and Spyder 5 using "XYZ LUT" profile.

Interesting things to note:

1. When I export the photo after editing it in Photoshop the colors of it appear the way it was in Lightroom.
2. When I change the color mode to CMYK in Photoshop the photo changes to a correct color (like in Lightroom).
3. When I save the psd file in photoshop and then view it in Lightroom to compare it to the original, the colors look the same.

So we can agree that it's the Photoshop that messes the colors up, but why?
P.S. I work with raw .CR2 files.

Answer 1

Finally, after days of reading I found an answer!

In photoshop go to:

Edit>Preferences>Performance>Graphics Processor Settings>Advanced Settings>
And set the Drawing Mode to Basic

Restart the program.