Wow, that is a bit OP. 

ive experienced this as well and had a strange glitch with stars (i think) on a map

i started a map and had this pop up

zooming in one level showed this 

the same space but now the sun like orbs are gone and no indication that stars are there using FOW caused the game to crash so im not sure what was there

I don't want a game with fewer planets per light year than galactic civilizations two. I like a I of of habitual planets on the game extreme, or not. What I was saying is that what I would like to see is when I pick tight clusters that there were just as many stars and planets as loose or scattered. In order for this the map would have to change size for scattered, tight, or loose clusters. What use is a bigger map if there are very few planets I can find. This defeats the purpose of bigger maps.

I noticed this and played with settings on several start ups. Keeping stars, planets, habitable planets, and extreme planets at abundant, I turned down asteroid and resource frequency to uncommon/rare, and I had significantly more habitable and extreme planets. I didn't notice a big difference between a resource frequency of uncommon vs. rare, but with it set to at least uncommon, the percentage of stars without planets went from about 65-75% down to about 50%, and there seemed to be more frequent groups of habitable planets instead of a single planet.

To give some real numbers:

In my first game (with asteroid and resource frequency at common), I had explored about 35 stars in the first 50 turns, and 24 had no habitable planets (69%). The total number of planets I had discovered was 9 habitable (0.25 per star) and 4 extreme (0.11 per star). This means I discovered about 1 habitable planet every 4 stars, and one extreme planet every 10 stars. This was not fun.

With asteroid and resource frequency set to rare, I had explored about 50 stars in 60 turns, and 28 had no habitable planets (56%). The total number of planets I had discovered was 19 habitable (0.38 per star) and 12 extreme (0.24 per star). This means I discovered abut 1 habitable planet every 3 stars and 1 extreme planet every 4 stars.

So with asteroid and resource frequency set to rare, I saw an increase of roughly 50% more habitable planets and about 120% more extreme planets.

I've started about 10 games and played them out to turn 50 or so, and this has been pretty consistent, though there aren't always so many extreme planets relative to habitable planets.

So, the bottom line is that the number of habitable and extreme planets seems to be directly linked to the frequency of resources and asteroids.

Not sure if that will help... I may have just been getting lucky. But maybe it's something to try...