I too am sceptical about those V-band variations in the KWS, Robin. In spite of the tight errors bars.
The interesting thing is there whilst there are many photometric surveys of faints stars, there are very few surveys of bright stars like Megrez.
I think we should all take a leaf out of Alan’s book (me included!) and look up at the sky with our naked eyes to check if there is something out of the ordinary. After all, it was only a few weeks ago that Betelgeuse was observed to be dimming.