CST - IR drop on a relay switch

Hello, I have a strange result on IR drop simulation. The circuit is very simple, it's just a connector J6, two tracks and a relay switch RL12. It is a four-layer PCB, all four layers have the same copper pattern. The result should be a current density distribution on the tracks.

I've set a 1.0 V power supply with Rsource = 1 mOhm at the connector, the tracks are of power and ground net classes, and the relay switch is I/O device with 1 Ohm current drain. I would expect the current was slightly below 1 A, but 546 Amps are drawn from the connector. Do you have an idea what went wrong? It seems there is a short-circuit between the two yellow arrows.

CST Studio Suite