Classic - Improved Shadow Bolt Talent - Clarification

Anybody know if the Improved Shadow Bolt talent (which adds a 4-stack debuff for increased shadow damage to a target) is reduced by players other than the lock for which it proc’d? For example, if a mob gets the debuff from a Shadow Bolt crit and then a warrior and rogue hit the target 4 times, does it go away?

If i remember correctly, this is how it worked in vanilla. Has to be direct Shadow damage to get the stacks to tick down, doesn’t matter who hits the target. Could be you, a Shadow priest, or a Warrior using Shadowfang. DoTs still benefits from the damage increase without causing the stacks to go down.

Not sure how it works in SoD though, if that’s what you are talking about.