That happened when your were in a team and a hight LV member leave or disconnect.
Player's LV will change back to normal, but NPC still at highend LV until you log out.
NPC only need a shoot can sent you to grave directly.
For example.
LV40 player joint LV10 player's map. NPC LV changed.
LV40 player leave or disconnect. NPC still keep at high LV.
NPC give you a shoot, game over.