@Lisbon I ended up going with your method, just made the most sense to me. It took me a while to notice the color cast too, but it bothered me once I did 😅
there's a very faint green/purple cast at along the focus line (around 30% up from the bottom)
I will be honest, but I had a hard time to find it.
I believe most of us won't even see it.
See if this works for you.
Duplicate the background and change the blend mode to colour.
On the BG copy, with the Clone Brush Tool set to 0% hardness start cloning from a close area (Similar brightness).
This will only affect colour. Not texture.
This strange colours are due to support layers that I used just see better the problem.
On your computer it will look fine.