The most recent was when going through a traffic circle and all of a sudden the car just took off. The pedal was not depressed

.
Oooh... that's (very) nasty. I like B mode because it asks as a brake at slow speed, which is good. I'm now wondering whether this could happen at
any speed ... or is it happening when the car was moving (pedal
was depressed) and then released to neutral position? E.g. I've been using B mode when manoeuvring out of a tight car space. If it accelerates there, that's not going to be pretty. Given the acceleration in the IX50 is pretty awesome, it would not be awesome if that happens.
Yes, please report ASAP. Having the dealer test it will be useless (unless it happens while they drive it, which it won't) - just the mere fact of raising it should immediately institute a code review.