While this might be my improper operation of the config, turning the feature of additional, randomised skins for passive mobs off within it hasn't worked even after closing and reloading the game of several times. I have not as of yet explored to see whether this is true of any other feature due to fear of damaging my worlds, though fortunately I made backups immediately before I ran into this issue and can call upon them in case it should become necessary.

FML Log: https://pastebin.com/zeV9UyBY

Understood; thank you for your swift response!

Config (texture variation and all sub-options set to 'true' in config menu): https://pastebin.com/AriZyCs7

Screenshot (texture variation and all sub-options set to 'true' in config menu): http://oi67.tinypic.com/71jpyh.jpg

Config (texture variation and all sub-options set to 'false' in config menu): https://pastebin.com/Nwnw2ctQ

Screenshot (texture variation and all sub-options set to 'false' in config menu): http://oi64.tinypic.com/2emlh5f.jpg

I'm not sure about you, but that second config you sent has the random textures enabled.

I've just double-checked both the in-game config menu and the config file and there is definitely an inconsistency between the two. I could try editing the config directly to fix the issue; then again, that seems remarkably like dealing with the symptoms of the problem rather than the cause. What would you suggest?

It is? Apologies, I didn't realise; I won't bother you any further, then! Thank you for bearing with me. I look forward to seeing more of what Quark has to offer in future!