Originally Posted by
sfo789
Most common place I see this is the pmUA 772s that service IAD<>SFO -- 6B autoblocks because every intl flight treats that seat as crew rest, but UA RM will sell the seat (ie with 3 seats remaining, UA shows J3 even though there are only two unassigned seats, since 6B remains blocked). Then the "unneeded" blocked seat becomes available at T-48 or 24.
LAX-LIH on the 752 constantly generates this question. They will sell the F cabin to 16, but 4A/B are blocked until T-48.