That AND I feel like the rockwool really needs to be precharged for a day in a rooting solution. then I hate that you can't really use the damn hole. why do they make that fuckin hole so damn big!
Take bigger cuttings with thicker stems. Gives them a jump on rooting and they only need to soak for 20 min I have tested every time period and it does not make a difference.
Also press the edges of the hole around the stem to make a snug fitting.