I have a mavic pro and had it for a few months before. Only now I start having the time to properly test it.
I experienced the watercolor effect as well and couldn‘t get it fixed.
So I decided to reset the mavic down to the point of delivery and downgraded it via Assistant 2, then upgraded back to the current firmware.
I reset the camerad settings via dji go as well and deleted and reinstalled it as well.
After that the pictures were fine in standard and normal mode (both 4K and 2.7K, 24fps).
Switching to a different color profile worked fine also (d-cinelike).
Only setting the softness -2 again resulted in unusable soft, oil-painting like footage.
I will also test this some more.