Triggered stuff does not grant ward despite using mana and the wording on both affixes on gear and the lost knowledge passive would indicate otherwise.
Despite there being a wording in the game of “directly casting” that could be used to clarify this. With the wording as it is right now you should assume you would gain ward when casting spells indirectly but you don’t.
For example Harbinger of stars crit meteors do not grant any ward via the lost knowledge passive or % of mana spent gained as ward affixes.
While I could somewhat understand the passive to not work as it reads “when you use a skill” the affix on gear does not specify in any way how the mana has to be spent. Either way the wording on both is bad as it is.