That's kuz 1.12.2 version is out of date. Get the 1.8.9 version
There are servers optimized for 1.12 +, they do not come with 1.8 version. So we want an update for the high version of LQB
LiquidBounce 1.12.2 is currently trying to load its heads from https://headdb.com which has been shut down. That's why heads do not load properly anymore. Will be fixed in LiquidBounce 1.13.2 or LiquidBounce 1.12.2 b3.