Stupid AMC7135's

Yes. In order to better understand how this works, please take a look at the XM-L2 graph djozz provided here:

(post #51)

Either graph will do, but the XM-L2 T6 graph is the bottom one. As you can see, every 0.1v is accounting for approximately 0.5A of current. Your linear driver will limit current as intended only when Vf is low enough to give it at least 0.12v of headroom above the Vf at the desired drive current.