Are you talking about the current on the generated phase while under load. Or current on the pass through phases under load. If so how does capacitance limit current. Seems to me the load would dictate current draw. Just asking.
It actually corrects PF on either, depending on where put. If put on the pass-through, per your original question, it corrects the PF "looking into" the RPC. The "balance" capacitors correct the "outgoing" PF on the generated leg, if they are used, and that tends to raise the output voltage, which is why they are used.
But... short story is that capacitors draw current that is in advance of voltage, and inductors are opposite, they draw current that lags behind the voltage. Those leading and lagging currents are called "reactive" currents. They are actual measurable currents, but do not contribute to producing any power.
So, since they are opposite, one can counteract the other; the lagging current combined with the advance or "leading" current, adds up to be zero, which leaves only the "in phase" current.
When "looking into" the RPC, the motor is pulling a fair bit of lagging current, plus some "power current" that is in-phase. The capacitors pull "leading" current. Looking from the mains input, the "average" of those two is zero, which leaves the actual "power" current only.
The size of capacitor is sized to the inductance such that it mostly counteracts the inductance, leaving only the "resistive", or "in-phase" current, which is what produces power, and is required. Usually the correction is made only 85% or 90% so there is always a little of the "reactive" current left, to avoid over-correcting.
So it is actually a genuine net reduction of total current.