Thanks for the pointers to other forums Andy, I appreciate it.
Given the mulitiplicity of problematic artifacts and the overwhelming majority of 5D users who transcode their files, it seems plausible that some of those artifacts may be attributable to the transcoding process.
A point in support of that is that even though many 5D users were saying that some of the transcoding programs available injected no problems into the workflow, Canon felt compelled to create a transcoding program of their own, on an expedited basis.
If there were no problems, why was Canon compelled to offer a transcoding program of their own and why the hurry?
But I'll bring my thoughts to those other fora.