I am not sure whether bug or suggestion but anyhow that Yggdrasil can stack buff effects with its branches, should be changed.
I knew about stacking branches with rings and thought it might be fixed. But 6 times potion effect on 1 tower is gamebreaking. Also Yggdrasil with life potion is sick together with ring you get 140 hp get a few by luck and the demon sword gets really op.
In the end Yggdrasil helped not nature but other towers just to carry the buffs over.