When you hear something about George Soros on the media making some sort of claim about his hedge fund's position, it is safe to assume that he already that move.
So for instance, when he said "bitcoin is a bubble" he probably had some shorts, but personally I think he didn't bother shorting, his goal was yo buy the dip.
Now he has bought probably in February, and he doesn't want the price to get stagnating, which is why he released these news. Soros controls a ton of media out there.
Nothing is spontaneous, it's just calculated moves. Now it's yet to be seen if Soros isn't old enough to understand why he should be stacking on Bitcoin instead of temporarily manipulating it to get his fiat up. If he is smart (and we must assume he is) he should know by now the fact that fiat is dead and all hedge funds with a brain should be building strong Bitcoin portfolios if they want to be relevant for the next 100 years.