EDIT: Reading the bug reports of others, I now realize this is not an issue with empty skill slots, but just with changing legends via build-templates. As soon as you do it, things get messy. ~~So, there seems to have been a partial fix to this issue, but that fix only works, if all your skill slots are occupied. If you leave some skill slots empty (because you don't have enough skills on that legend yet), all skill orders will be messed up again after changing build templates. This is quite a bummer for me right now, because I wanted to have the assassin for its speed-buff as a simple "travel-form", but I don't intend to use it for fighting, so I don't want to level it up any further right now. I am level 27 right now and ended up getting that third assassin-skill to make this work for now, but I expect the issue to return once I hit level 31 and the elite skill is unlocked.~~ I also found this rant on reddit about the issue:https://www.reddit.com/r/Guildwars2/comments/dozq31/revenant_utilities_are_currently_trashed_with/