SwiftBlog

PHBII p 220:

Invigorating
If you are trained in Endurance, you gain temporary
hit points equal to your Constitution modifier when
you hit with a power that has the invigorating keyword.
No invigorating power grants temporary hit
points more than once during a turn, even if you hit
more than once with that power.

If the power never grants the hit points, you have nothing to stack. Thank you.

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