I fixed this!!!! I went into C:\Program Files (x86)\Steam\steamapps\common\sid meier's civilization v\assets\DLC\Expansion\Gameplay\XML\Terrain and into the Civ5Features.xml.
I went to Feature_TerrainBooleans section and change grass into plains for jungle. It works with SDK now!!!
So I did this for both the Expansion and Expansion2 folders and it fixed the Editor painter/plopper to put jungle on plains.
It also fixes the in-game Civilopedia entries for plains, it moves the jungle to plains.
I checked all 3 of the game's civilopedia versions, vanilla, G&K, BNW, and jungle was on plains in vanilla, yet something happened in G&K that moved it to grassland in the civilopedia, and it carried over into BNW's civilopedia as well, most likely not intended as the map scripts still put it on plains, and 3 food tiles would be very overpowered, especially with Citrus&Bananas or combined with trading post/university.
Seeing even the newest scripts that came with the latest DLC, scrambled nations (nov 2013), they put jungle on plains (2 food base yield, 1 food/1hammer when chopped), so that must be the way I feel its supposed to be.
I don't know if this affects multiplayer though.