I've been stocking up on these for the engineer unlock (Wellington Beck), finally decided after the latest hotfix to try selling. TL;DR, it's broken and doesn't work.
Beck unlock: Sell a total of 20 Multimedia Entertainment, Classic Entertainment and Cat media to bartenders.
If it's 20 of each, then fuck that I'm not doing that grind, it's taken me dozens of hours just to get the 20 I had.
Here I've got 13 cat media and 7 classic entertainment ready to sell.
After selling, I check for messages
Nothing, so I relog, and open up the engineer page
DO NOT SELL YOUR CAT MEDIA, MULTIMEDIA ENTERTAINMENT, OR CLASSIC ENTERTAINMENT if you want the engineer unlock.