Similar buffs (like a shrine) have a buff length indicator ring around the icon above the skillbar, but Dread Shade does not (neither does Infernal Shade?). Other skills with shown “stacks” (like maelstrom) have buff length indicators. I can only guess it’s because the skills target your minions? But I don’t think it would be difficult to have a pseudo-buff on the character that does nothing but tracks the timer for the buff to properly show above the skillbar (so it behaves like other buff timers that affect the player (i.e. shrines, maelstrom)) that’s created at the time of casting (since I don’t think there’s a way to “dispel” it in Last Epoch … basically securing that the pseudo-buff and the actual buff will always have the same timer length). And if the player specializes into Infernal Shade’s “Soulfire” node, then maybe just keep the current behavior that shows stacks but doesn’t show duration.
Thanks for your consideration!