Arch Linux 64bit, OpenJDK Java:
openjdk version "1.8.0_112"
OpenJDK Runtime Environment (build 1.8.0_112-b15)
OpenJDK 64-Bit Server VM (build 25.112-b15, mixed mode)
All graphics settings at maximum, VSync and VBOs off.
Pre-generated fire does not always emit light properly in the nether. When something is updated nearby, it often starts emitting light.
Two screenshots below:
1) Fire soon after Nether generation
2) Same location after some action (fighting Ghasts and stuff)