Bug dreams of ice?

I dont understand dreams of ice amount decreases each time i recover health when it should increase, or it should be atleast a constant 25%defense gain.
And collective unconcious give as much as dreams of ice the first time but not the others.
By the way im running cleric so why greater healing perks do well on unbidden miracle from nutrient blood ( *1.5 heal ) but not on unbidden miracle from mend ??

Stat gains have diminishing returns past a certain point, so that’s why you’re gaining less benefit from Dreams of Ice over time.