Keterys quoted it above -- Heroes of Shadow, page 101, second column, bottom paragraph.
It's not an advertisement. It's in the printed book, stated explicitly.
You're being stubborn.
And the power is not in agreement with that, do to the absense of exceptionary text.
As I already said, I'm well aware of the intention. And I'm well aware of what is missing from the power to make said intention correct.
Is there a single word in the power that says that the power can last longer than an encounter? No. Not one. Zero. Is there a single word in the power that says it ends at the end of the encounter... yes. One. "Summoning." Had the power stated 'The power ONLY ends when _________' then it would have been exceptionary. The power does not, however, exclude other ending conditions placed on it. No contradiction = no exception.
RAW does not match RAI. That's a statement of fact, not being stubborn. If a power wants to be an exception to the rules, it, like every other power that does so in the entire game, must provide a contradiction to those rules. This is why Power Strike got errata'd to No Action... because while it was
intended to be used with a scout's at-will power, it could not, in fact, do so as it was written. Thusly... it was changed to reflect the intention. It wasn't -designed- for that purpose however... it works with a slayer just fine.
Conversely, if this power is intended to have staying power, should it not have better defenses so that it can last beyond an encounter? The power's design does not match the power's intention, and in cases like this, sometimes the power changes to match the intention. Other times... the intention changes to match the power.
This is a case where Intention and RAW do not agree. And until they address the difference, one cannot state the rules 'clearly state such and such' when they clearly do not. What is written is that it lasts until the end of the encounter. What is described about it is some other thing. I don't doubt they'll add in something to ensure it can behave as desired. What cannot be said, however, is that it says it magically creates exceptions to the rules simply because we want them to be there. That's not how 'Rules as Written' works.