Planet Generation Bug?

[newageofpower]

I was rerolling a fairly wet Siwa, trying to get that "best university in sector" history tag, but halfway in I left my computer for an hour or so, which went to sleep/screensaver whilst playing the planetgen music.

I came back to finish planet generation... somehow I have a 12 billion population planet that somehow has no cityscapes and is almost purely agricultural.

imgurDOTcom/a/1X6xlbo

(Replace 'DOT' with '.'... this forum security is really, really annoying)