[...]

I noticed that on this laptop with USB3 ports, AEP won't work plugged in
direct (LMP, using a similar NXP chip are the same). They need to be
connected via a USB2 hub in order to work. Maybe that's something to do
with it.

Are you by any chance running from within a VM on a mac? I've seen similar behavior in that scenario.

Also, have you tried running as sudo just to verify it's not a permission issue? I seem to remember this happening for me once in a while too when I was running power measurements, and only some combination of fully resetting the probe and booting the machine did the trick, for whatever it's worth.

-Christoffer