From here:
https://bitcointalk.org/index.php?topic=5096261.0Original price: Gifted with several 2017 Kialara Silver Series - To The Moon pieces
Materials: .999 Silver 1oz coin
Denomination: None
Mintage: 117/130*
Artist: Maxfield Mellenbruch
Known errors: None
* On 10/16/2017 Max uploaded a post in the To The Moon production update blog saying that he has acquired 117 Error coins. In a later post, uploaded on 12/19/2017, he speaks of 130 error coins.
The blog post referenced in that link is apparently now gone, but the error itself is stated on
https://wiki.coin.community/Kialara_Silver_Series_2017_%E2%80%93_%E2%80%98To_the_Moon%E2%80%99#Error_Coins"During minting some of the silver coins were created with the wrong back design. These coins were given to customers whose orders were delayed because of this. This is the only Kialara piece that can be graded."Edit - thanks @mbitr!