I think it did occur with both Wilder and Bradley, but perhaps more clearly with Wilder.
There was some evidence that it did occur in some of the gubernatorial elections in the 2000's, but never as pronounced as it was with Wilder or Bradley. It was dwindling over time
In some states in 2008, IA, for example, Obama did overpoll, i.e. run well below his polling numbers; absolutely nobody expected it. Where I was looking for it, PA, it didn't happen.
Something that did seem to happen in 2008, that hasn't been reported too much, is that Obama underpolled in states with high Hispanic populations, that were of Mexican ancestry.
So, in other words, there's no Bradley effect.
