Special daily objectives

ulquiorra4th

Good day
As far as i remember
If we didnt do the special daily objective, the objective itself can be stack

Or not?
I forgot to complete mine and i thought it will be stack with the new 1 but it never
So i lost my last milestone on solo objective in saga
I lost the 4-5 6* rank up gem

willrun4adonut

They don't stack. But you can miss one day and still be fine.