My only idea is that after the voting the stocks that you used for voting will be locked and not traded anymore. And You will receive certain number of NewCo shares. Now, if you looked at the EC's Q&A documents there was a question when the new shares will be traded. Well, The EC states that they may not be traded for a long time, or they may not even be traded at all. They do not know and that is not EC's job anyway.
So, All those traders bought this at the ground level are selling now so that they can use their money in other stocks instead of waiting for the NewCo shares.
Or just say MMs are playing with it...
Best to all longs
AIMHO
Climber