Hello,
No new information to anyone here but for future reference we have this mentioned here so hopefully others are able to find it: https://support.circleci.com/hc/en-us/articles/360018651374
We are also looking into detecting ARM images so perhaps we can implement some kind of warning in the UI.
If you are interested in CircleCI adding ARM support, please cast your vote and share your opinion here: https://ideas.circleci.com/ideas/CCI-I-900
Thank you!