Custom Weakness Rule Elements proc for each damage type

[JamzTheMan]

Given the below Custom Weakness RE, a Strike with property runes (say, cold, electricity, force) will add the Weakness 4 times.

{
  "definition": [
    "action:strike"
  ],
  "key": "Weakness",
  "label": "Blessed Counterstrike Weakness",
  "type": "custom",
  "value": "7"
}

Given that Weaknesses (shouldn't?) stack, these should be aggregated together and taken once. (granted there may be arguments for "instances of damage" so worse case an applyOnce or applyAll option could be added to let it be single or multi instance weakness?)

https://2e.aonprd.com/Rules.aspx?ID=2317
If more than one weakness would apply to the same instance of damage, use only the highest applicable weakness value. This usually only happens when a creature is weak to both a type of damage and a material or trait, such as a cold iron axe cutting a monster that has weakness to cold iron and slashing.

[stwlam]

An instance of damage is basically a damage type. I agree there's a need for "contact" custom weaknesses similar to how water and salt work, so we'll look into adding an option for a custom weakness to identify itself as such.