P: Lightroom Classic: Editing raw file in PS from LR loses profile

Exporting to DNG and opening into PS (through ACR) definitely works.  Multiple workarounds exist:

• Downgrade to ACR v12.4
• Save metadata (.xmp) prior to "Edit in PhotoShop 2021"
• Use "Open as Smart Object in PhotoShop" then double-click on layer
• Export as DNG, open the DNG in PhotoShop

That said, the issue in ACR should still be fixed so that "Edit in PhotoShop 2021" works as expected and as it used to.  My preferred workaround until the issue is resolved is the save metadata just prior to editing in PhotoShop.  But hopefully I won't have to use it for long!

Thanks @John_R_Ellis for the thorough analysis!

DNGs contain their develop settings in an XMP metadata section in the file (just like TIFFs and JPEGs)

Exactly and probably why I can't replicate since I'm just working with DNGs. So in the meantime, converting to DNG could be the fix. 

I can't replicate the problem with DNGs. DNGs contain their develop settings in an XMP metadata section in the file (just like TIFFs and JPEGs), the same XMP contents as would be in a sidecar. I confirmed with @dprosk's DNG that it contains the actual LUT, not a reference, just like a .xmp sidecar.

So no issues using DNG?

Thinking a little more about this, almost certainly the LUT is getting dropped on the floor unless there's a .xmp sidecar.

When there's a creative-profile LUT, the .xmp sidecar contains the actual encoded LUT, e.g.

crs:Table_43CE5AF1D6EC3B3338CDB7A0CB099BA6="Lir00.ks!*{EZHy|E35{f2.M{CyyQaOV:pl#x]zq*gVp2BMFuBD(2{nYG$WKWHQ#prLX0+kTr-QTh$'nQ=NtnM{%'ns.?Kq|16/Q`MmF5R:3(yOp4UVDGxEfpAerO2f*6KB-1t/Rt03}^+kLt9D-8)8riaqNzqN[gC4n%H'^ThDC4Fd6p]
...

But internally, LR's develop settings just contain a reference to the LUT, which is cached in the Camera Raw engine:

RGBTable = "5F18C8C737DCE48D81659D934F9C9D35"

LR must be passing just the reference to the cached LUT, not the contents of the LUT (unless there's a sidecar).  If PS has been freshly started, it won't have the LUT in its cache.  But if you first open the raw directly in PS, it will have the LUT in its cache, and when you later edit the raw from LR, PS will find the LUT in its cache.

It appears this bug is limited to creative profiles (.xmp) using LUTs.  I can't reproduce the problem with creative profiles that just use develop settings, and I and Andrew can't reproduce the problem using custom camera profiles (.dcp).

Apparently, when you edit a raw with a LUT creative profile in PS, and there is no .xmp sidecar, the LUT is getting dropped on the floor.  Perhaps this is a bug in the hidden mechanism by which LR passes develop settings to PS when there isn't a sidecar.

The example DNG posted by @dprosk involves a creative profile with a LUT. Here's what the relevant internal LR develop settings look like:

CameraProfile = "Base Profile V4", 
Look = {--table: 2
    ...
    CameraModelRestriction = "Canon EOS R5", 
    Name = "CF Landscape V4", 
    Parameters = {--table: 3
        CameraProfile = "Base Profile V4", 
        ...
        RGBTable = "5F18C8C737DCE48D81659D934F9C9D35", 

@andrew_rodney I haven't a clue what might be different about that profile.  It also happens with another third party profile I have and looks like @John_R_Ellis also reproduced it with a LUT?

I've got that profile and yes, it exhibited the issue in your video. None the less, this doesn't happen on this end with ALL non Adobe DCP camera profiles. So the question is, what's wrong/different with that profile? 

@7348725 - you are lucky...the rest of us are seeing it all the time...  😞  here is a video of it:

https://youtu.be/c2L6hyEyT10

@John_R_Ellis When you edit a raw photo in Photoshop that has a non-Adobe profile, Photoshop loses the profile.

DCP Camera Profiles? I'm not seeing this with my own custom (non Adobe) profiles which is all I use.