Different staffs are different base weapons and do not have total overlap in blessing pool. This is intentional and has been discussed at length already. Please at least do a cursory search for existing reports before making your own.
It was explained on the patch release that different MKs of the same weapon would share blessing pools. You can tell from the fact that staves do not have the same blessing pool that they are not variants of the same base weapon.
It could have been outlined clearer but regardless of how you may feel about it it is absolutely intended and not a bug. This has been confirmed multiple times I’m afraid.