Bug: Guldan's Hunger For Power and selfheal

Lvl 7 talent “Hunger For Power” increases Drain Life healing only from 62 to 65 per tick (on lvl 7 character), dont looks like 15% increased spellpower. Damage spells are correctly buffed by 15% btw.
I guess this talent does not reduce our selfhealing, so healing should be 71, but if it should reduce, then some calculations are wrong anyway, it should be lover than 65, because its +15% sp and -25% healing.
Same for the “Healthstone” on lvl 13, “Hunger For Power” increases its healing by approx 5% for some reason. Should it even affect life% based ability?

Also, lvl 4 talent “Improved Life Tap” not working at all, but it is known issue, I guess.