HD tag missing on new purchases if SD version bought prior

There is a strange bug existing on one's cloud purchases regarding the "HD" tag being present.

If HD versions of movies are initially purchased, the "HD" flag appears below the movie's title (under Purchases) as expected.

However, if the SD version was purchased in the past, and the user later purchases the HD version of the same title, the "HD" metadata tag will not populate, regardless whether the "Download HD When Available" checkbox is checked.

See screenshot below - I just took advantage of the $4.99 HD "Office Space" (which I had already purchased an SD version of), but the "HD" tag did not populate. In comparison, "The Firm" was purchased for the first time as the HD version the other day, so the tag populates as expected.

I had contacted iTunes Store support about this a few months ago regarding a different title, but the Level 1 support agent had no idea as to the root cause. Unfortunately, I was not directly passed onto a Level 2 (or higher), so as far as I'm aware, no solution exists.

Wondering if anyone has any insight to this...

Thanks,
Steve