My suspect without looking at a raw file , is that the sky is just a bit clipped in the raw data. Without highlight reconstruction that appears as magenta.
To rule out or confirm , turn off everything except white balance and exposure (everything you can. Including highlight reconstruction). And see if its there , and see if it goes away (or not after lowering exposure quite a bit).
If its there with lowered exposure and no other modules except exposure , then you can try getting rid of it by enabling highlight recovery and if needed play with the threshold or try different algorithms. (But the default ‘opposed’ should be fine to be honest ).
Once its gone at lower exposures , you can set exposure to where you want it and edit the image as you see fit.