That's the one, bingo. It was a new line of smaller MBs, so I misremembered it being Smart. The issue though was most certainly with the software overcompensating the roll in the wrong direction. I would've not remembered it otherwise :)
The A class didn't have active suspension. I believe it was a mechanical issue and solved with a stiffer front anti-roll bar and other suspension geometry tweak. Though there is a possibility the ESP was tweaked to apply the brake under such circumstances I think that could do more harm than good. I could be wrong, it was 1997..
IIRC the non-ESP MB Sprinter also had stability issues.