I expected it to function like it does for Forager with Perception and and Exploration, thats why I spent lp to go to 55 Masonry before finishing the quest. After I finished it still was only 55.
Can confirm, just completed the lvl 2 masonry quest and didn't get +20 masonry, but I may have gotten it at lvl 1, I don't really recall. Either way there's a bug there.