One more time. It just getting strange. UK 1/2 penny 1967 Km896. Narrow rims thin waves.

Some history. A few or many years ago, I put this up.A 1967 1/2 penny thin waves. Well Tony said it is most likely a thin planchet. Not have a good scale at the time and Tony to me a God when it comes to UK coins.
Well now I have a better scale. It is heaver and thicker than another one I pulled.
UK 1/2 penny 1967 Km 896 Narrow rim Thin waves

5.82 grams, 1.64 mm thick, 25.5 mm Dia
Close up on I in GRATIA

And waves

Here is one I pulled for a control

5.71 grams,1.58 mm thick, 25.5 mm Dia
Well can not be a thin planchet. Because it weighs more than the control. and is a little bit thicker too. Could it be a vanity of narrow rim. Iam thinking more likely a over die cleaning.
Your thoughts Thank you daryl