Anyone else know of this distinction, or does this evoke feelings of unticntion?

Interesting study you have suggested, Musick.

The American Heritage Dictionary definition of "uninterested" concludes with this reference to a "Usage Note" under the definition of "disinterested":

Usage Note: In traditional usage, disinterested can only mean “having no stake in an outcome,” as in Since the judge stands to profit from the sale of the company, she cannot be considered a disinterested party in the dispute. But despite critical disapproval, disinterested has come to be widely used by many educated writers to mean “uninterested” or “having lost interest,” as in 'Since she discovered skiing, she is disinterested in her schoolwork.' Oddly enough, “not interested” is the oldest sense of the word, going back to the 17th century. This sense became outmoded in the 18th century but underwent a revival in the first quarter of the early 20th. Despite its resuscitation, this usage is widely considered an error. In a 1988 survey, 89 percent of the Usage Panel rejected the sentence His unwillingness to give five minutes of his time proves that he is disinterested in finding a solution to the problem. This is not a significantly different proportion from the 93 percent who disapproved of the same usage in 1980.

re: does this evoke feelings of unticntion?

No, it evokes feelings of discombobulation.