Hi Dan. Did you ever get to the bottom of this I am having the same issues. We are dealing with RED ONE.
The only time Avid will not recognise the files is when the Camera has duplicated (or what I hear chunked) inside an RDC folder. 7 .r3d files are created. They appear duplicated.
Avid won’t AMA these folders but RED CINE X will read and process them as one entity.