A source across a parallel resistance

This is the circuit from the lecture, running. Change it and the answer changes with it:

• Click any component value to edit it, or drag components to rearrange.
• The wrench opens a step-by-step analysis — it chooses a reference node and writes the node equations. Leave its Domain on the DC operating point for this deck.
• The crosshairs probe reads a node voltage or a branch current, so you can check any intermediate result rather than only the final answer.

Change the 3 mA to 4 mA and the two forms stop agreeing. Put it back and change the 4 k instead: $v_S = R\,i_S$ has to hold, or this is simply a different circuit.