The reason the lights draw differing current is because electricity is like water with respect to "resistance."

In theory, even two identical lights may draw differing currents simply because of imperfections, or the mounting and temp of the light emitter or the length of the cord they attached by.

I don't know how these led light regulators work, but the "voltage cut off" levels are functions or "results" of two other variables - current and resistance. And in the case of Dinotte, there "current cut offs" as well voltage controls. (short circuit protection?)

What I can safely say is - powering two lights will affect each light's regulation circuit. Whether or not you notice it when reading voltage only. (this part is not BS) And then of course there may be an on-battery protection circuit that will not be affected.

The unexpected results part - which is BS - means that one light or the other may go into power saving mode prematurely, and battery run time may seem unpredictable.