MC 1.12.2
Forge 1.12.2 - 14.23.1.2556
Foamfix-0.8.1-1.12-anarchy
OptiFine_1.12.2_HD_U_C6
6GB RAM Allocated

Full log: https://pastebin.com/Q153Dnun
Crash report after force closing the game: https://pastebin.com/7YLbkAKc

Farseek/Streams dev here - this seems to be the same as PG85/OpenTerrainGenerator#80 and is now fixed on the Farseek side in delvr/Farseek#35.