I see in the description of the Maurya hero building, the Harmya, it says "Territory Root." I agree with @chrstgtr, this seems like a random addition to the civ. I'm curious why it only applies to Maurya and Persia. If there is a historical justification, I'd understand I guess.
I did a quick test and it looks like the Persian hero building, the Apadana, also has this feature of maintaining root without a CC, but there is no mention of it in the building's description. Maybe one of the developers/ BAs can add it in if this feature is to continue?
Thanks for answering my question.