A few things going on:

1. the misleading "congrats on your Medallion Upgrade -- PSYCHE!!!! It's just the C+ upgrade you already got a while ago" email has been widely reported

2. the lack of an upgrade yet means revenue management still thinks it will sell a lot of those F seats especially on a route like LAX-ATL

3. FT is not necessarily representative of the traveling population as a whole, but it's not a cinch that 5 C+ seats occupied = only 5 DM/PM on the flight, because some people are so averse to the possibility of a C+ middle seat that they're leaving the "request C+ upgrade" box unchecked. (Although if I were such a person and only 5 seats were occupied in C+ I'd go ahead and opt in for the upgrade, esp. given 2-3-2 on the 767)

if it remains 15F then they might clear some comp UGs at T-1d or something. Don't be surprised if it goes to the gate though. People may also SDC for lie-flats on a red-eye.