You're not going mad, there was a hot spot mark on Bell's bat and the Aussie commentators were banging on about it all day. Some blogs I read afterwards were calling Ding Dong a cheat for not walking (Australian hypocracy at it's finest).
The commentators seemed to think Bell knew he'd hit it and chanced his arm that hot spot either wouldn't show anything or it'd be so faint that the 3rd umpire couldn't be certain. Snicko later confirmed there was an edge.
These were all fair comments as I'm sure he hit it too, however what pissed me off was how they then failed to mention an almost identical incident involving Micheal Clarke at The Gabba.