Think to have found them and further down.
@Wlodek also mentioned …
… In case of blown-out spots in all RAW channels, where on their boundaries you have only G1/G2 blown-out, you can get in previews pink/magenta artifacts after WB correction, …
Re-visited some images with RawDigger and could see where the various channels were clipped due to exceeding the (available) dynamic range. I’m wondering if this is responsible for unexpected color casts.