Went today (30/11/2018) and when I arrived the guy said it's closed for the next month.
Annoying especially given the ball ache with public transport to get there (as detailed below).
Be aware that there are no buses from Bau to Krokong or the cave (supposedly). So you either have to get a grab or hitch a ride, which isn't too difficult.
In the end I went to the Wind Cave which was pretty crap. If it weren't for the lovely people who gave me lifts it would have been an absolute waste of a day.