If you increase with Masterworking a Tempering stat what gives you passive skills.
They always never switched to “blue” but you got the higher skill lvl in the skill tree.
Also if the Stat is only +1 you get nothing…because you get only 25%…but If you temper a +1 skill it should be +2! So that the minimum what you can get is +1 to the skill after Masterworking!
Also many times there was a +2 Version of the passive with the legendary recipe. Many times it didn’t show +2 on the item if you got, but you got +2 in the skill tree.