For reference, here is the first link with the issue. I've started this at the post where a member has identified the cause, and an overflow issue on the Roku.
"The problem seems to be that, because it was an anamorphic video, the aspect ratio value stored in the video's bitstream was so large that when the Roku OS did the calculation to figure out what aspect ratio it was supposed to be displayed at, the result was likely so large that it exceeded the maximum value their OS could handle (bad Roku...should have an error handler for this)."
Then today, another user with a similar issue comes in.
In this post you can read through the thread and see its the same issue. The SAR on this is 8:9 and the DAR is 4:3. The video is 720x480. It is anamorphic. The Roku will only render the top section of the screen with the image. This is happening to this user with LiveTV. We cannot control the stream delivered to his Roku. We can only present it to the video player.
The issue is, there is no mechanism on the Roku to refuse to play this media, it instead chooses to just play it incorrectly. If instead, it refused to play it. Gave an error indicating such, the video player fallback recovery in our app could react and then transcode this correctly and not have this problem. Or.. if the Roku could somehow know the SAR is incorrect, and just use 1:1 for it instead, thereby streching this 4:3 to 16:9 incorrectly. But that is better than what it is presently doing.