Guild Wars 2

Thief shortbow #2 skill Cluster Bomb should apply 3 stacks of bleeding if not detonated according to its tooltip. If detonated, it splits into three smaller bombs which each apply 1 bleed stack.

Bug: The undetonated bomb only applies 1 bleed stack instead of 3.

That’s more of a tooltip problem, it should be listed for undetonated and detonated.
The one stack from the big bomb is intentional, because the big bomb gets a blast finisher feature

You are right that either the tooltip or skill is bugged, but I’d rather take the word of a developer. Logically thinking it feels that the skill itself is bugged, since you have one big bomb with 3 bleed stacks, which splits into 3 small bombs with 1 bleed each.