There is a little issue with Carpenter's Blocks and Gregtech. Quote from InfiTech 2 modpack issue tracker (https://github.com/JasonMcRay/InfiTech-1.7/issues/121):

If you set the color of a Carpenter's Blocks item to a GregTech Ore and then destroy it, you get an item called "gt.blockores.0.name". If you mine it, you get regular Iron Ore.

How to reproduce: place a Carpenter's Pressure Plate, right click with Lignite Coal Ore to set the color, destroy pressure plate with Pickaxe. Place the stone-looking Block and mine with Pickaxe.

The Ore you used to paint the block seems to lose its metadata, and mining it without metadata seems to drop iron ore by default. Shift + left click with a Carpenter's Hammer removes the original ore block.

Exploiting this could give you lots of iron early game, destroying the balance.

This seems to be a bug present everywhere with GregTech and Carpenter's Blocks.

I just did a quick test. Some recent code I pushed retains the original block itemstack so blocks always drop as they should. Rendering is a mixed bag since it won't get tile entity data for covers.

Verified fixed on my end some days ago, so closing this. Rendering issues on the other hand are normal for these types of blocks.