Program: 31432
Project: 31432
Buggy source:
/** 
 * renders all ItemStacks and returns hovered gui item stack for later render pass
 */
@Nullable public GuiIngredientFast render(Minecraft minecraft,boolean isMouseOver,int mouseX,int mouseY){
  GuiIngredientFast hovered=null;
  if (isMouseOver) {
    hovered=getHovered(mouseX,mouseY);
  }
  RenderHelper.enableGUIStandardItemLighting();
  RenderItem renderItem=minecraft.getRenderItem();
  TextureManager textureManager=minecraft.getTextureManager();
  renderItem.zLevel+=50.0F;
  textureManager.bindTexture(TextureMap.LOCATION_BLOCKS_TEXTURE);
  textureManager.getTexture(TextureMap.LOCATION_BLOCKS_TEXTURE).setBlurMipmap(false,false);
  GlStateManager.enableRescaleNormal();
  GlStateManager.enableAlpha();
  GlStateManager.alphaFunc(GL11.GL_GREATER,0.1F);
  GlStateManager.enableBlend();
  GlStateManager.blendFunc(GL11.GL_SRC_ALPHA,GL11.GL_ONE_MINUS_SRC_ALPHA);
  GlStateManager.color(1.0F,1.0F,1.0F,1.0F);
  GlStateManager.enableLighting();
  for (  GuiIngredientFast guiItemStack : renderItems3d) {
    if (hovered != guiItemStack) {
      guiItemStack.renderItemAndEffectIntoGUI();
    }
  }
  GlStateManager.disableLighting();
  for (  GuiIngredientFast guiItemStack : renderItems2d) {
    if (hovered != guiItemStack) {
      guiItemStack.renderItemAndEffectIntoGUI();
    }
  }
  GlStateManager.disableAlpha();
  GlStateManager.disableBlend();
  GlStateManager.disableRescaleNormal();
  GlStateManager.disableLighting();
  textureManager.bindTexture(TextureMap.LOCATION_BLOCKS_TEXTURE);
  textureManager.getTexture(TextureMap.LOCATION_BLOCKS_TEXTURE).restoreLastBlurMipmap();
  renderItem.zLevel-=50.0F;
  for (  GuiIngredientFast guiItemStack : renderItems3d) {
    if (hovered != guiItemStack) {
      guiItemStack.renderOverlay(minecraft);
    }
  }
  for (  GuiIngredientFast guiItemStack : renderItems2d) {
    if (hovered != guiItemStack) {
      guiItemStack.renderOverlay(minecraft);
    }
  }
  for (  GuiIngredientFast guiItemStack : renderOther) {
    if (hovered != guiItemStack) {
      guiItemStack.renderSlow();
    }
  }
  RenderHelper.disableStandardItemLighting();
  return hovered;
}

Fixed version (ground truth):
/** 
 * renders all ItemStacks
 */
public void render(Minecraft minecraft){
  RenderHelper.enableGUIStandardItemLighting();
  RenderItem renderItem=minecraft.getRenderItem();
  TextureManager textureManager=minecraft.getTextureManager();
  renderItem.zLevel+=50.0F;
  textureManager.bindTexture(TextureMap.LOCATION_BLOCKS_TEXTURE);
  textureManager.getTexture(TextureMap.LOCATION_BLOCKS_TEXTURE).setBlurMipmap(false,false);
  GlStateManager.enableRescaleNormal();
  GlStateManager.enableAlpha();
  GlStateManager.alphaFunc(GL11.GL_GREATER,0.1F);
  GlStateManager.enableBlend();
  GlStateManager.blendFunc(GL11.GL_SRC_ALPHA,GL11.GL_ONE_MINUS_SRC_ALPHA);
  GlStateManager.color(1.0F,1.0F,1.0F,1.0F);
  GlStateManager.enableLighting();
  for (  GuiIngredientFast guiItemStack : renderItems3d) {
    guiItemStack.renderItemAndEffectIntoGUI();
  }
  GlStateManager.disableLighting();
  for (  GuiIngredientFast guiItemStack : renderItems2d) {
    guiItemStack.renderItemAndEffectIntoGUI();
  }
  GlStateManager.disableAlpha();
  GlStateManager.disableBlend();
  GlStateManager.disableRescaleNormal();
  GlStateManager.disableLighting();
  textureManager.bindTexture(TextureMap.LOCATION_BLOCKS_TEXTURE);
  textureManager.getTexture(TextureMap.LOCATION_BLOCKS_TEXTURE).restoreLastBlurMipmap();
  renderItem.zLevel-=50.0F;
  for (  GuiIngredientFast guiItemStack : renderItems3d) {
    guiItemStack.renderOverlay(minecraft);
  }
  for (  GuiIngredientFast guiItemStack : renderItems2d) {
    guiItemStack.renderOverlay(minecraft);
  }
  for (  GuiIngredientFast guiItemStack : renderOther) {
    guiItemStack.renderSlow();
  }
  RenderHelper.disableStandardItemLighting();
}