Update:
I measured the Vf of the LEDs on the highest mode.
Light 1: 3.81V at 5.16A
Light 2: 3.87V at 4.52A
So Light2 has higher Vf even at lower current - that’s bad, right?
The Cree data sheet doesn’t go above 3A, so according to djozz testing, one might expect to see 3.7Vf at 5A. So the Light2 LED which has 3.87Vf at 4.5A seems like an abnormally bad (below spec) example. Would you agree, or am I missing something?