Just downloaded the 3.2 version, logged in the server and went on the graphical settings to set mipmap to 4, waited for those 50/60 seconds and then all the textures were wrong.

Then I turned mipmap off, thinking that that could have been the cause: after that everything turned white when I was getting near it

And the lava is lapis ore

This is just a forge/minecraft bug that the texture atlas gets messed up if you change mipmaps (or even just reload resources) while in-game. If you change it and relog, or change it in options.txt before starting it should be fine.