Sinclair Lightning Scroll is sometimes not working

[RuinKnightSir]

With some ults, Lightning Scroll does not prock for Sinclair.
These ults are:
Billy, Celeste, Graves, Holliday, Paige, Paradox, Rem and Wraith.
Sometimes other ults if the damage takes too long.

This is specifically Sinclair and these ults work with Lightning scroll on their characters.

 

[RuinKnightSir]

I've read that it is because the enemy ultimate icon disappears and if you Lash/Ivy ult high enough, the icon disappears and you don't prock Lightning Scroll.