There is something wrong with Hardening Persistence? It works as stated in most combination apart from one upkeep skill combination.
Facet of Nature + Embrace of Darkness. This combo gives 9 stacks but upon canceling Embrace it cancels all stacks of Hardening Persistence even those gained from Facet of Nature.
It is major drawback because to regain 2 stack You need to reapplay Face of Nature to get back those 2 stack that went missing after cancelling Embrace.
Other skill combos don’t cancel 2 stack of Hardening Persistence.