The 12ngg does not show in my coinbase wallet history...I don't understand this? Only the 36ii5 address does...
This does make sense.
From the coinbase FAQ:
Coinbase began implementing SegWit across our platform on Wednesday, February 21, 2018. We will progressively update all customer Bitcoin addresses to be SegWit-compatible (SegWit addresses) over the following week.
So, the 12ngg.. is somehow a different address (not from coinbase).
Did you use any software wallet on your PC / mobile ?
Quoted for easy-access-link:
https://i.imgur.com/QRSxfrW.jpg