This was claimed to have been fixed a couple of patches ago, but many traits and abilities that provide bonuses to attributes are still granting fixed bonuses rather than scaling with effective level, and this is causing them to give wildly differing values based on effective versus actual level.
Some examples:
Flesh of the Master: https://wiki.guildwars2.com/wiki/Flesh_of_the_Master
ALL mesmer mantras: https://wiki.guildwars2.com/wiki/Mantra_of_Recovery
Many of these skills / traits that claim to offer an attribute bonus are doing one of two things incorrectly:
1) Their bonus scales with effective level and then is affected by level-scaling causing them to inflate or deflate massively.
2) Their bonus is fixed as long as your effective level is the same as your actual level, but then the bonus is affected by level scaling causing it to get weaker and weaker as you gain levels, eventually granting zero bonuses or less than half of what they should.
Many of these bugged skills ARE abuse-able under the right conditions. A mesmer can enter WvW at level 11 and become nearly invulnerable to direct damage so long as they channel a mantra, because for a level 11 mesmer, channeling a mantra gives over 7000 bonus toughness.
Please change all of these skills to scale solely based on effective level as they should. As it is now, none of them work properly.