Looks like the additional mid wing structure visibly changes flow below it (logical), and causes lower pressure, hence some detachment? Which is also logical if the main wing was not designed to work with this small winglet.
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I find the images difficult to interpret. If the driver used SM mode, that could explain some things...If you compare to Audi, then it looks strange so yeah I think there is some SM mode noise in this picture.
https://pbs.twimg.com/media/HBmBaBhXgAAzn0d.jpg
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The Ferraris are on their way out of the pitlane which is why the flow viz looks so different compared to the Audi. You can see the green color flying off the rear wing, up into the air and the tires are also blank/shiny.