I think she appeared in the Dior corporate magazine a while back, just as a model rather than a contracted "face", so maybe that's where the images are coming from? I think that was a year or so before she signed her contract with Estee Lauder.
I didn't like Gisele for Chanel, and I don't think I like her much at Dior either. Her appearance doesn't come with any sense of loyalty to these brands. When it's a fashion campaign, we expect change - but consistency seems to matter when it comes to beauty advertising.