The times it happens for me, I'm pretty sure the ABS isn't activating. They're corners where the apex of the corner is also the vertex in elevation, so that the road drops away as the corner unwinds. It must be something to do with the unweighting at the crest that causes the software to think something imminently bad is going to happen so it cuts regen, but apparently I've been lucky to not reach the threshold where it thinks it needs to apply a brake to prevent a crash.
I'm lucky not to have hit a pothole hard enough to trigger this. Ouch.
Does turning off traction management also turn off the regen cutout? Maybe I'll go out late tonight and give it a try when there's no traffic.