Guild Wars 2

Like if it have 30% chance to apply a bleed when you crit. Will it give 60% if you have two of them?

Second hand experience is all I have. A member of my guild stated that no they do not stack but was talking about a specific rune, but had a X on proc effect.

I’d like to know if this is true for all runes, not just proc runes. Or if it even is true on all proc runes.