LTSpice transient simulation of LC circuit
It does the same in micro-cap. Basically, with any simulator, it tries to ascertain the steady-state initial conditions and, in certain circumstances, it needs to be explicitly told what those initial conditions are. This is one of those circumstances; a current source feeding a capacitor.
The simulator tries to determine the steady state conditions then, once evaluated, it will produce a transient response. But, what are those steady state conditions you might ask. For a simulator, it makes use of the leakage resistance it applies to every circuit node and the default value for micro-cap appears to be 200 MΩ. I get a peak voltage of 2 GV and 2 GV/ 10 amps = 200 MΩ.
In some circumstances (such as these) you need to &quot;force the hand of the simulator&quot; so that the initial conditions are defined as in .ic V(1) = 0.