It's normal from a display point of view, mine reads 90 on the dash from about 70 to 100 via torque app, it's vags attempt to stop people stressing over small fluctuations in temp that are in the normal range for the car.
If your temps drop back below the high 80s when the car is warmed up then your thermostat is probably stuck open though, mine was dropping down into the 60s on cold nights when cruising on the motorway, changing the thermostat sorted that.
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