max hp blue nodes have always been 2%, not 2.5%. you are misremembering.
secondarily, there is a bug with the UI’s display, where it is rounding down, resulting in things that should say 20% saying 19%, and stuff saying 2% saying 1.9%, stuff saying 70% saying 69% instead, and so on. it’s just a UI / rounding error. you aren’t actually missing any stats.
put these two things together and we arrive at a logical explanation for your “problem”