The bug

The following is based on decompiled version of Minecraft 1.10.2 using MCP. All method and class names are the names used in the decompiled version.

The public void deleteTexture(ResourceLocation textureLocation) method of the net.minecraft.client.renderer.texture.TextureManager class is not removing the entry for the provided ResourceLocation in the mapTextureObjects map.

public void deleteTexture(ResourceLocation textureLocation)
{
    ITextureObject itextureobject = this.getTexture(textureLocation);

    if (itextureobject != null)
    {
        // suggested fix: add this line
        this.mapTextureObjects.remove(textureLocation); 
        TextureUtil.deleteTexture(itextureobject.getGlTextureId());
    }
}

This is very likely still the case in 1.11 snapshot 16w42a:

• Class: byu
• Method: public void c(kq ?)

public void c(kq ?)
{
    byv ? = b(?);
    if (? != null) {
        byw.a(?.b());
    }
}