I am using the PowerBI #2.40.4554.463 64-bit (October 2016). Noticed that two different tables (which has no relation )can not have the same name for the custom created(Renamed) column. This should not be the case when tables has no relation?
Thank you for your report, this is currently the way Power BI implemented.
If you would like the team to consider changing this please feel free to add a suggestion at: