Week 2 -Rare Spawn Hunt- do bosses spawn only one time?

Week 2 -Rare Spawn Hunt-

do bosses only spawn only one time or can we farm multiple times again and again ?

You can farm them over

Tried to farm the boss at the waterfall once again one day later but he didn’t spawn again??

Do you have 100 % spawn chance guaranteed only once one time ?

It’s 100% as long as you start a new game.

Never failed to spawn for me.