I've noticed that some copycats place double when using the Mirror Wand:

Also found the same (or similar) problem with:

• Copycat Box.
• Copycat Board.
• Copycat Catwalk.
• Copycat Byte.
• Copycat Layer.
• Copycat Half Layer.
• Copycat Slice.
• Copycat Vertical Slice.

Other inconsistencies include the fact that mirrored copycats don't place when you place an original one in "ghost mode", but this also happens with Create's own copycats.

And lastly, mirrored copycats aren't removed when the original ones are Shift-R-Clicked with a wrench.

Can you test the newest version again? We have reworked some blocks since then and I can't reproduce this bug now.