评论来自 Tolavan

Along with being a drop from various Shadowlands rares (i.e. Bubbleblood & Smorgas the Feaster) and lootable from Tribute rewards of Covenant Callings, 熔岩瀑流 can also be obtained as a possible reward from Shadowlands WQs. I received an ilvl 145 Infernal Cascade conduit today (9% dmg increase) as a reward from doing the Bastion WQ Flight School: Falling With Style.

According to the in-game Adventure Guide, Margrave Stradama the last boss of Plaguefall also drops higher ranks of this conduit:
Normal = ilvl 158 conduit, 9.9% dmg increase
Heroic = ilvl 171 conduit, 10.8% dmg increase
Mythic = ilvl 184 conduit, 11.7% dmg increase
And according to Wowhead, Mythic+ may drop higher ranks

Edit: Just opened a Tribute of the Wild Hunt right now and got an ilvl 171 Infernal Cascade Conduit from it
Edit 2: Received an ilvl 184 from opening a Tribute reward from a Calling (forgot to note which specific Tribute)
Edit 3: Got an ilvl 200 (12.6% fire dmg increase) Infernal Cascade from opening a Tribute of the Court which I recieved from turning in a Calling

Can confirm you are also able to find the higher ilvls of 熔岩瀑流 (along with other conduits) from opening Tribute rewards from Callings