This looks like an exchange have tried to short the market, by adding massiv fake and negative volume, the 24h coinmarketcap volume was 50.8 billions on the first picture and down to an normal volume of around 35 billion on the second picture.
And and its looks like it was only bitcoins volume that was manipulated, from the normal 24h volume of around 10 billions up to a massiv 25 billion volume.