I have noticed that after looking at this thread https://forum-en.gw2archive.eu/forum/professions/engineer/Update-The-Juggernaut-effects-please/first#post6118577.
Showing the effects of Juggernaut on a Scrapper (https://www.youtube.com/watch?v=uBZ5cYhLFl8&feature=youtu.be&ab_channel=JordanWebb) the only effects are the auto attack, everything else is the normal effects.
This is quite annoying since every other class able to use a hammer have effects on most, if not all their hammer skills, including the Revenant which is in fact the same day Scrapper became available on HoT release.
I find this quite unfair for us, Scrapper (Engi) players who are wanting to go towards the legendary Hammer just to have all the effects of the Legendary with ONLY ONE skill with the effects which is the Auto Attack, skill 1.