Most of my shots taken in shade have a slight magenta or blue cast. Just grab the blue or magenta slider slider in any program and drag toward negative or removal. Do not desaturate on the master level (all colors) or you will lose some of the natural colors and intensity in the browns, greens and greys. BTW, I do find the cedar bark does have some natural red/magenta, but you are referring to an overall cast.
JR
I also sometimes see a magenta, or red, or blue cast in the shadows at high ISO, or in deep shadows at base ISO, especially when using my 'el cheapo' Nikon DX5300, which is my walk-around camera.
However, I have no problem in removing such a cast in Photoshop. I'm not familiar with LR. Photoshop serves my purposes. To remove any cast in Photoshop one clicks on the 'Image' heading at the top of the Photoshop page, then 'adjustments', then 'Hue/Saturation'. This brings up a small window as depicted in the attached jpeg.
All you need to do is select the color which you associate with the cast, such as magenta, then move the pointer to the part of the image where the cast is most apparent, click, then reduce saturation with the slider. Sometimes what you think is magenta is not, and the color name in the window will change accordingly.
