Okay..first off, this might have been a glitch or just my seeder acting up...
When i was mining for diamonds, I FOUND A TON of ore...Not the point....while i was mining i found a mine shaft...It wasnt an abandoned mine shaft..There was a couple NPCs in there...after i got most of the diamonds , i explored the mine shaft. I cam across UNDERGROUND NPC villages...It was weird...Even weirder was that there was another tunnel leading out to the surface with yet another NPC village....

Am I the first person to come across such a weird thing?