The Mythic items orientation seems to be the same for all of them (May flip along vertical axis), but the actual chest is located in a different spot to where you need to dig. It appears you are more so digging for sparkling areas rather than the chest.
Here is a link to the layout of the mythic items. It may be flipped along the vertical axis to have the diagonal going the other way.
https://imgur.com/a/AcO0QQE
Here is an example. You can see that the chest doesnt line up at all with the sparkling areas that need to be dug up.
https://imgur.com/a/rQ5umH4
Hopefully this helps out a few people who I've seen struggling to dig up the Mythics with the skewed up digboxes.
Edited by mattiellosa on May 29, 2020 1:26PM