Looking for Ember's Heat

I am trying to finish the Meteorologicus I: The Experimental Scepter achievement, and I am 12/15. I am only looking for monster drops right now, and I'm starting with Ember's Heat. I have been killing Embers all over and they are not dropping it at all, which is weird because most other parts of the achievement are dropped quite easily or quickly. I don't want to jump to the conclusion that this is bugged, but it's really weird and unusual for this game to ask a player to stay in one isolated pocket for hours on end for an achievement, whereas the rest of the game is more about exploring and such (in my very casual experience).

I need Ember's Heat, Ice's Bite, and Spark's Energy still. Are there better known farming spots or methods to get these? Is there some bug that I don't know about either or alternative method to just grinding mobs mindlessly for hours on end?

trying to remember where I got them

Sparks have a good spot in Harathi Hinterland, near the Bandit leader spawn in the spider forest.

Embers I think I killed in Fireheart Rise, there are a couple areas with a lot of them.

Ice Elementals I recall killing on the steps to Arah. There are areas, fairly close to the Narthex, that have quite a few. I'm sure there are better places though...

The area northwest of Earthshake WP in Frostgorge is where I went for that. If I were to do it again I would probably go to the area south of Wide Expanse WP in Dredgehaunt Cliffs.

The wiki also has fairly extensive listing of all the different spawn locations of these.

If a little empathy helps I had a heck of a time getting the Heart of the Ember to drop for Rodgort I. Took me a few hours in various locations before it finally dropped. It happens, it is just sometimes left up to the gods of RNG to determine when. Good luck and I hope the tips above work for you.

You can also try switching to a different character. Spent a long time with no drop for the ice elemental drop on one character then switched to another and got it on the second elemental killed. Might have been just RNG, it's hard to test.