Is there a difference? bug or not?

Hi,

Is there a difference between these stun nodes. In the first picture theres a dotted line only under the word STUN, whilst in the second picture theres a longer dotted line under the two words STUN BUILDUP. Are these two different in any way? or can I as a warrior safely use the node in the first picture and it will go towards my regular STUN BUILDUP skills? I noticed that other skills near the node in the first picture also only have dots under the word STUN (third picture as an example)

The text inside the tooltip window all say the same, however.