While using RED footage shot with the DSMC2 Helium 8k S35 we were unable to render out DNX36 using Cortex v5.2.1-b16486.(Errors out). We defaulted back to v5.1.1-b16139 and the DNX36 render out.
We received the sample footage but had no problems rendering it using the same version of Cortex and the default Avid/DNX36 config. If possible export and send the logs from the job in which you tried to do the render.