Using the hue equalizer in the defringe module somehow leads to extreme, incorrect defringing. This is even with the equalizer set to almost nothing for an unrelated hue and to 0 for the hue that is getting defringed inadvertently.
It appears this happens because the water in the background has a blue hue. So it is defringing the blue, rather than the red/green/yellow hues. This could be intended/expected behavior, but it is also unintuitive given that the water is a relatively large and homogenous area.
Since this is a new phone model, it is possible that new, currently unsupported features have been introduced into the DNG structure. If you “repack” this photo with the latest Adobe’s DNG converter, it looks quite different, much less saturated.
So this does not seem to be a RT-specific issue, but here ends my “wisdom”, I am not competent in this area at all.