Had to re-post this as I originally thought it was a bug but now I’m not so sure as it could be intentional. After doing some more digging it turns out that the POC Rune of Ritual doesn’t appear to trigger Runes of Invocation when the Channeling or Empowerment Buff has been applied from shrines or Kurast Undercity Braziers, in my case it was my TEC (Earthquake) Rune as the Earthquakes weren’t being applied… I’ve heard from others in bug reports that equipment effects/buffs that require primary resource to be spent are being affected this way by the shrine/brazier buffs as well.
The Channeling effect appears to make it so that you don’t ever have to spend your Primary Resource while active rather than giving you unlimited primary resource, because of this method/formula I think it makes sense as to why the POC Rune of Ritual doesn’t activate.
Because that rune specifically needs you to spend a certain amount of Primary Resource in order to trigger the attached Rune of Invocation and because the Channeling Buff while active makes it so that you can’t spend any Primary Resource, therefore not allowing your Rune of Ritual to trigger the Rune of Invocation until the Channeling Buff expires.
Might not be a bug technically or maybe it is, maybe it wasn’t intentional to work this way. But it would be great if the devs coded in the amount of Primary resource you WOULD have spent while the Channeling Buff is active and allowing the POC rune to still count it as spending Resource even if you haven’t technically lost any, at least while the Channeling Buff is active at least.
Might even call this a request now rather than a bug report, a request to update the formula for Channeling and Kurast Undercity shrine/brazier buffs to still allow POC rune to detect Resource that would have been spent to allow Runes of Invocations to trigger as they normally would. As well as equipment that has effects that get triggered by using primary resource getting calculated too of course as it appears that not only runes are affected going by old bug reports/posts.