Bug: CPU vs GPU BRAW grading produces different results

Hi! I was taking the online color grading course with Daria (great course BTW).

During the last part (BRAW and HDR), I firstly noticed that turning on BRAW Highlight Recovery didn't do anything. And my waveforms were one bar lower in the highlights section. And then as I tried to follow along, I also noticed every change I made was having a huge impact compared to what I saw on Daria's screen, making everything look garish on mine. Even the completed project looked garish. I initially thought this was a color space issue, but fiddling with the color management settings, nothing ended up matching what was expected.

So I went into System settings and Decode Options and noticed that
"Use GPU for BRAW decode" was turned off. I turned it on.
"Use GPU for R3D" was "None". I turned it to "Decompression and debayer".

I don't know which of the two settings fixed it - I imagine the first one - but that made everything compliant with what I was seeing on Daria's screen.

So this brings the question - should GPU and CPU based BRAW grading be so completely different that one looks natural and the other one looks completely garish? With CPU, my waveform went above the 1024 line somewhere... but with GPU it stayed below.

Edit: I'm on Windows 10 (Home), 17.2.1, latest NVIDIA Drivers (GTX 970)

And slightly concerning... luckily I don't think I have this issue at the moment... how long has this difference existed... hopefully if I open an old project that uses BRAW material, it won't now look completely different that I've enabled the GPU decoding.

Maybe someone from BMD will comment, but there can be unexplained behaviors like what you describe in the Color page with older GPUs, like the 970.

So this brings the question - should GPU and CPU based BRAW grading be so completely different that one looks natural and the other one looks completely garish?

Simple answer is no, it shouldn’t. Why it did, hard to say, unless someone can reproduce the issue. Gpu being an issue in cpu decode path… maybe, given that cpu decode relied at least partially on gpu too, for some braw files.

I will try tomorrow to write down steps to reproduce.

I have noticed differences in BRAW processing between my GTX 970 and my GTX 1070, with the 970 being unusable.