DLC - Athens becomes client state of Persia?

[Ancient One]

I'm playing a game as Persia with the new DLC, and at some point I get a message that Athens becomes a client state. This completes the Persian mission for the conquest of Greece, though at the time I wasn't at war with Athens or any other Greek state, and indeed no Persian had set foot in Greece. I played a Hellenes interloper decision on Athens in a previous turn, so it might be because of that, but I don't feel like I really earned the completion of the Greece mission. Is it really a good idea to allow client states to be made with regional decisions (assuming it's due to that), especially since AI client states never betray their overlord?

[Pocus]

That's not related to Hellenes interloper, this is related to Athens being besieged by Sparta (or another Greek nation) and in the process of losing the capital. In a last minute move, they prefer to bow before mighty Persia ...

[Ancient One]

Thank you for the clarification. It appears Athens was indeed being besieged by Sparta.