With an LED voltage and current become inextricably linked. Take a close look at this post by djozz with a graph showing MT-G2 voltage vs current. Follow the blue line, ignore the red one. Note that as voltage increases (blue line goes up) so does current (blue line goes to the right). This relationship is always present; there is no avoiding it.
What I think you probably saw were your cells taking a big 20A-25A+ beating while producing a ton of resistive losses in all areas of the wiring, but especially in the carrier. You did bypass all springs, right? There would also be losses in the FET, in the traces and vias on the driver’s PCB, in the traces on the MCPCB, and in the switch.
Note that all these resistive losses cause voltage drop across those things where the losses occur. As we saw above, the voltage controls LED current. Less voltage means less current. Therefore these losses are what keeps your current down in the range where the emitter doesn’t pop.