Why does daily reset quit Valkyrie event?

Kerneas

Luckily, there is overflow of the event currency, but why was my started quest terminated? Iirc, in the past it wasn't a problem to start one day and finish the other, even tho daily reset took place (as long as the event itself wasn't taken down). I don't want fights back or any currency that I have "lost", just a reason for this. Thanks

Gamer

Because the quset rest every day