Is it normal to miss elixir ingredients?

[The_Evidence]

Is it possible to clear the relevant dungeon without getting NPC alchemist's elixir ingredients that are only available there?

For example, I think I've killed everything in the Lake of Nur and the Maze, but I'm missing the Pouch of Luminous Horror Dust.

Should I go back to these areas and pick them over carefully for hidden rooms or did I just get unlucky?

Thanks!

PS
I'm new to Maj'Eyal, but not to roguelikes. Really enjoying it so far.

[bpat]

You'll see more Luminous Horrors the future, don't worry too much about missing them for now. The only ingredients I ever miss completely are Wyrm ingredients.

[Massimiliano Marangio]

The monsters are (mostly) determined randomly; if they don't spawn in an area then you can't collect the corresponding ingredients. Try to go further, Luminous Horrors may also appear in some vaults in other zones.

[kyuubee]

elixir ingredients aren't guaranteed to find

[Doctornull]

Some critters including dragons, undead and horrors can spawn in Farportal realms, so that's a decent last resort for some of those.

Every Adventurer which tries to ambush you on the world map each have a 30% chance to drop a random ingredient on death.

Some critters have special zones (mummies for example), other special zones (naga, ritches) will be revealed when you travel for plot.

[The_Evidence]

Thanks guys, that was exactly the information I needed.