I have the same bug but only when recording on server. Windows 8.1 64x Java 8 Update 181 Minecraft 1.12.2 Forge 14.23.4.2750 Replay Mod 2.1.3 OptiFine 1.12.2_HD_U_E2 (without shader) and other mods...
Afaict this should also affect handedness but I cannot reproduce it using that setting. Will have to actually change my skin at some point.