Merchants (Starbound)

After I passed the game I started to notice this problem: NPC-merchants, such as wandering and merchants in the cities began to die, if wandering just died on the spot as soon as got into my review, in the cities they were dying when they embarked on their trading post so to speak, among other things, the apex near the gate to the last boss which sells augmenti also dies.
How to treat and did not understand