When should the new "Magic" component blueprints start dropping?

So, this is an odd one… When AoM came out, I first checked it with my Conjurer who was on ultimate, and for him, blueprints for the various “Seal” components started dropping from everywhere - treasure troves, bosses, even just regular urns.
On the other hand, my Blademaster is level 82 on Elite now, and only now did I find ONE “magic” component blueprint for the Prismatic Diamond, after killing Ben’Jharr.
It’s weird since my Conjurer was way below 94th level, when those Seals can be used, but my Blademaster is way above the 75th level when those new components would start being useful. So, where can I find the blueprints? Only Nemesis stashes?

I have yet to find one from a Nemesis trove (though I’ve only really hit Benn’Jahr repeatedly so far I think) and was thinking I should do some SoT runs instead. Found lots of blueprints for some of the new components like Living Armor but no Runebound Topaz or anything of that tier yet.

For some odd reason, I guess if I did not reach the later areas yet, chances of a Nemesis are higher in the areas I did find - 'cause I now encountered Benn’Jahr twice in the Blood Grove.