I read the wiki. I know how it is SUPPOSED to work.
I just can't see it work, and I still don't know the difference betwen an upkeep skill and a herald skill. I **guess **that a "Herald" skill is Glint's facet.
In any case, it doesn't work, or the bonus is somehow hidden. I didn't notice any dmg increase either with or from any upkeep skills.
PLUS: a sample of "brilliant" support explanation:
"Forceful Persistence is a skill that increases character damage, and is buffed further with active upkeep skills. As it has no icon, it will not show above your skill bar. Additionally, as you are able to see here: https://wiki.guildwars2.com/wiki/Forceful_Persistence, **it does not work when the character is channeling Glint**. As Facets are all related to Glint, you will not receive buffs, or any additional damage, when using a Facet."