As said in the discord bug report section, Flame and Blaze not being affected by any power signets is most likely an intended behaviour since they are Special abilities not tied to the weapon specialty.
So far, power abilities and any abilities tied to weapon specialty are affected, hence the inclusion of grenades, Spirit Blade and Frenzied / Invigorating Wrath, but not other Special abilities.
Any other abilities the OP described (so excluding Flame / Blaze) not being affected by the power effect from the agent is definitely a bug though.
Good to see theirs already a Bug Report in for this. Disregard my message on steam I was rather late to discover this as Sarah Skelly was getting close to 50 and wanted to test if they were a better option.
Anyways have confirmed same results as you with Warlawurru and Terry
Yes, I am making ANOTHER bug report as it still isn’t corrected and has been reported since March 21. I just don’t understand how the basic damage bug on agents can be repaired, yet the 8% increase in the BLADE Power ability Swallow Cut is just ignored for 6 months+. Neither Sarah Skelly nor Warlawurru increase the damage. Rest assured if this affected an AR power ability, this would have been fixed ASAP.
In fact it affects an AR ability, Incendiary Grenade (and other grenades too), which since is tied to AR speciality should be buffed (as Szalord explained above).
Spirit blade and all the grenades are listed as special abilities last time i checked so I would not expect an agent that states " +8% Power Damage and Healing" to affect these abilities at all.
but still the power neck signet buffs grenades and it makes sense since they are tied to weapon gimmick.
Just the same as hammer ( and others ) speciality is indirectely buffed by neck signet and + power agents also AR and blade ones should.
Check the logic somewhere above to understand why SOME special abilities have and SHOULD be buffed by power agents (they are already buffed by signets).
Also, what paololov said just above. That’s exactly the reason, in short.