Line 39 of \encounters\Legion.lua should have Elisande listed as encounter 1872. At some point in development she might have been 1743, as EJ_GetEncounterInfo(1743) still links to her but with a blank loot page.

What region are you in? For me (enGB) 1743 has loot, 1872 does not.

Like I assumed (which is why I asked for region), it's the Galakras problem all over again, Blizzard assigned the boss two IDs (see #8).

Proof:

I'll apply the same logic for her like I did with Galakras, thanks for reporting!