Thanks for sharing your thoughts on it. The van is so quiet and smooth that I'm going a little faster than I mean to be and I especially realize it when I'm getting ready to go into a turn. I'm not putting on the brake hard enough to engage the antilock brakes I don't think, but I'm having to press them a little harder than I would have needed to if I had eased up earlier. I'll try easing up some getting ready for a turn and less braking during the turn and I'll see if that helps.I had a 2nd-gen Prius that would do this, and I observed it in 2 different instances. The first was when the ABS activated during regenerative braking. The car wasn’t programmed to use the regen brakes for ABS, so it had to switch to the discs, and it would “let go” for a second during the switch. Which is terrifying when you need your brakes bad enough to engage the anti-lock, lemme tell ya.
The second instance is when the traction battery was full, and the car stopped accepting any more charge from the regen brakes. Same thing would happen. Also, when the battery is over-full, it uses the electric motor to turn the engine. It sounds like the gas engine is running, but it’s not; at least, not on gasoline. It’s just burning off electrons.
This second scenario sounds like what you’re describing. What I’m guessing is going on is that the transmission is not disengaging the engine, so the electric motor is turning the engine, which is pushing the car forward, fighting the brakes.