Most of the times it stays open on the US side. Only once has Sayona closed on both sides to my knowledge or I should say since I have been in Sayona.
PLL 3-years ago closed both sides when the Tesla announcement happened before battery day.
Lets hope a battery company is involved, not Tesla. You never want to have only one offtake partner. A battery company would make me happy anyone else will make me sad/mad.