Some Canon EOS R users have reportedly experienced banding issues with their new camera.
Michael The Maven discovered that artefacts appear as banding in RAW files when lifting shadows. After Canon release firmware ver. 1.2.0 for the EOS R, Michael tested again and compared firmware ver. 1.1.0 vs firmware 1.2.0., and found that the banding issue was gone.
Most user will likely never have an issue with banding but we recommend you update your EOS R asap.
Canon EOS R: