Circular dependency error

I have custom column which works perfectly. When I copy the table and copy the same custom column (with the relevant parts of the formula changed to reference the new table) it says there is a circular dependency. To be clear, the new table is identical to the old one, but is simply connecting to a new instance of Salesforce.

So my question is why does a custom column work perfectly with one table, and then has an error when doing exact the same thing in a n exact copy of the table?

To be fair, PBI was trying to ask me to report this as an error, so I guess it's just another example of how amazing PBI is...