ProPhoto Color Space producing green tint in PS only

[Tim5C9A]

When I`m opening a picture from LR Classic into PS i get a green tint in some of my colors.
To demonstrate the problem I completly desaturated the picture in PS with an adjustment layer, but still in some greys this green tint shows up.

Strangly, when i save the picture and the edited picture gets reimported into lightroom, there is no green tint there.
In the attached files you can see both versions (just the picture and the desaturated version) opened in LR Classic and PS at the same time and the green tint is definitly showing.

If i convert into SRGB when exporting from LR to PS, the colors in both program are the same, so i guess the problem must have something to do with the prophoto color space.

I try to stay in ProPhoto Color space all the time, so my export settings in LR are set to ProPhoto, and my Color space in PS is also set to Profoto as shown in the pictures below. 
I`m on an older Macbook Pro and the whole Catalina OS as well as Adobe cloud was set up from a clean install a few days ago, meaning i dont remember changing any of the standart settings.

Any ideas what could be wrong?

[Tim5C9A]

[D Fosse]

Yes, this is an old and well-documented issue in ProPhoto files. It was first reported with CS5.

It's happening in the conversion into the monitor profile. It's not in the data. The cause is most likely small inaccuracies in standard GPU rendering code that get amplified. ProPhoto is so extremely large that the "useful" values in the middle get very compressed compared to Adobe RGB or sRGB.

It doesn't affect everyone equally; it seems to depend very much on the type of monitor profile and which software built it. I use Eizo Colornavigator, and I see it with LUT-based profiles, but not matrix-based profiles.

Personally I see very little reason to use ProPhoto except in rare cases. It's not often needed. The disadvantages of ProPhoto far outweigh the advantages of the (rather unrealistically) large gamut. The compression in neutral values, particularly in the shadows, makes precise adjustments very difficult. And since you have to remap into a smaller color space at some point anyway, the risk of gamut clipping actually increases when using ProPhoto. Better to control clipping at an earlier stage. But that's just my opinion -

I added some saturation to the screenshot show it more clearly: