When a raw that's been rotated 270 degrees CW in the camera and flipped horizontal in LR is opened in Photoshop from LR, it opens upside down. To reproduce:
1. Turn off the option Catalog Settings > Metadata > Automatically Write Changes Into XMP.
2. Import a raw that's been rotated in the camera 270 degrees CW (90 degrees CCW). Make sure no .xmp file for the raw is present before you import. (The raw should have EXIF:Orientation = Rotate 270 CW.)
3. Do Photo > Flip Horizontal.
4. Do Photo > Edit In > Edit In Adobe Photoshop 2020.