https://pastebin.com/J3m83kpF
java.lang.IndexOutOfBoundsException: Index: 0, Size: 0 at java.util.ArrayList.rangeCheck(ArrayList.java:653) at java.util.ArrayList.get(ArrayList.java:429) at openblocks.client.renderer.item.stencil.StencilTextureManager$TexturePool$PoolTexture.upload(StencilTextureManager.java:96) at openblocks.client.renderer.TextureUploader.onRenderEnd(TextureUploader.java:31)

client connected on a Ubuntu Server

I have no idea what other mod messes with it (and why!?), but at least I made it harder to trigger.