Happiness Issue Under 1.55.376713.1

I am playing as the Yor and I noticed something that I do not understand while I was looking at the factors that contribute to the Happiness of a citizen (see screen snapshot below).  One of the factors that reduced happiness was called "This planet is full of life".  In previous versions, this only occurred if there were non-Yor citizens on the planet, but you can see that all of the citizens are Yor.  What is the "life" that the planet is full of?  Or is this a bug and the message is full of it?