I'm not sure what I'm doing wrong. I'm at the towards the end of my season pass. I did this part last season with no problem. I did my old moon quest, went to Jetina, and then my season pass window popped up saying I finished it. Last season, I did desert nagas. This time around, I did Gahaz Bandits... but when I went back to Jetina, the season pass didn't reward me and move on to the next thing.

Am I missing something that's real obvious? 

IIRC there is another part of the pass that requires you to do the all areas quest for 3k kills map wide. maybe that is the one you are missing or did it early and have to wait for refresh. (although i think it should still count im pretty sure it counts if you did the quest already just click the box on the pass) chances are you just missed the all areas quest. Note: this is not complete every quest there is one quest for 3k monsters of all over to be more specific.

Omg... I'm an idiot. I just saw it. I didn't scroll down the list of quests far enough. I thought "all regions" just meant "Hey! Pick any one of these you like to grind at and go!" 

don't feel too bad.  i did the exact same thing

I accidentally did the Daily beer one she gave.  I had to wait until reset, and there was a daily on the list called {Daily} Old Moon Guild Subjugation Request - All Regions.  Kill 3k monster anywhere.