Experiencing same issue
java version "1.8.0_25"
Win 10 64bit
FML Version 14.23.0.2508 - Minecraft 1.12.2
Have experienced this same issue in both Singleplayer and Multiplayer Worlds, when rendering (and not when just viewing replay) with or without nametags rendered. Attempts have been made both with and without Optifine, with or without other mods (forge or otherwise) installed. Renderings made of replays downloaded from the replayCenter experience the same issue.
Log attached was running an installation that includes Optifine, Schematic, Lunatrius Core, and Xaero's Minimap
Because the log was slightly above the max Pastebin size (for free users) I've split into 2
https://pastebin.com/aH4haVis (pt. 1)
https://pastebin.com/gnwbxC3b (pt. 2)