How is PPP (Puppet Political Parties) Supposed to Work?

[MegaTrain]

I did a search on the topic, and nobody seems to agree. It seems that the intent of the intelligence operation is actually to CONVERT the planet over to your empire, like Ship Capture.

But I just finished my first operation, and my report said "We have incited the people of xxxxx to break away from the xxxxx and form their own government, sire!"
But when I click on the planet, it looks unclaimed and unpopulated! Is this right?

So is PPP supposed to entice the planet over to your empire? Or do the results vary--sometimes they join you, sometimes they form their own new AI empire?

Or is this a bug? (There were other enemy planets and ships in the system, I suppose they could have battled, and I wouldn't have received a report.)
Thanks for your help!