It looks like it's going to be #36 "Charge" (Season 2, Episode 11). I still have #31-#35 (Season 2, Episodes 6-10) on my DVR so its not a biggie for me, and it also means we're likely to see #37 "Scream" (Season 2, Episode 12) on 9/9, finally in HD for DirecTv customers (as the first run glitched).
They actually did something right with the marathon stream for a change: they're showing #31-#35 all this week. With a surprising rerun skip to #36 on-air, I guess this is the best they could do.
I would say (for whatever reason) 9/9 will be the last 9-show Toonami for a while, and on 9/16 DBS returns to 11:30. Hopefully the good performers keep their timeslots and only certain shows (like JoJo and Lupin) are moved down.
And it looks like the AOT S2 final run count will likely be:
#26-#30: 3 runs each (premiere, marathon, rerun)
#31-#34: 2 runs each (premiere, marathon)
#35: 1 run (premiere only)
#36-#37: 2 runs each (premiere, rerun)
Kinda bummed that #35 only got on TV once, but I guess that's the way it goes. After all, MOST Toonami episodes are 1-and-done on TV! There has been no 2nd chance on Toonami TV for any episode of Samurai 7, Tenchi Muyo! GXP, Soul Eater, Blue Exorcist, Black Lagoon, Gurren Lagann, Hellsing Ultimate, Sword Art Online (I or II), InuYasha: The Final Act, Dimension W, Gundam Unicorn, Naruto Shippuden or Tokyo Ghoul, and it appears Lupin will probably suffer the same fate.