Hazardous Terrain Clarification

[Zyzygy]

RAW on Hazardous terrain says:

"If a Fireteam starts its Activation in base contact with one or more pieces of Hazardous terrain, it takes a Hit with Strength equal to the highest Hazardous value of those terrain pieces. Similarly, if a Fireteam moves through one or more pieces of Hazardous Terrain, it takes a Hit with Strength equal to the highest Hazardous value of those terrain pieces..."

Question: When Hazardous Terrain is created and dropped on a Fireteam does it hit for damage at that time? Or only on the affected Fireteam's activation?

Examples: Prince Unathi's Poison Rocket/Cloud, or the Dreadnaught's Chemical Fogger.

[retnab]

There are two times Hazardous harms the unit: when the unit activates in it, and when the unit moves through it.  Dropping the Poison Cloud (or whatever else) onto a Fireteam is neither of those, so the Fireteam is not harmed at that time.

[Aner-Dyfan]

I've been operating on the later "Only on the affected Fireteam's activation" with the caveat of if they are forced to move then that take the damage then.