Direct answer: your question sounds a lot like the question "is it possible to cast augury at a contract at all?" and we've already answered this question. I happen to feel that we've answered it incorrectly -- I really don't think the dm should allow this -- but we should solve that by fixing the wrong answer, not by answering it again on a different question.
(You've pointed out that there do exist contracts that produce effects within the 30 minute window, and that's technically true but I don't feel that it redeems the question.)
Side comment: I think it's really weird that you posted the question asking for "Rules As Written only". There are no rules as written about this. It's just the one paragraph in the description of augury. Asking the question in this way is going to attract a lot of wrong answers which claims to be Rules As Written but are actually shaky interpretations of that one paragraph.
This concern would seem to point to a close reason of "opinion based" rather than "duplicate".
Side comment II: A lot of the time, when we get questions of this nature ("here's something that should be open to DM interpretation, tell me the One Correct Way to do it, my question is slanted in a way that makes it look like I want X answer"), it's because people are trying to win an argument with their DM. We try to discourage people from using the site in this way. I'm not necessarily saying you're doing this, I'm just saying we get a lot of questions like this that are.
The most recent version of your question is better, because it asks a question which has a clear answer (even if it's still mostly a duplicate of the other augury-contract one).
But it still makes me unhappy, because it reminds me of playing "spot the loophole" with my more rules-lawyer-y players. "Spot the loophole" goes like this:
Player: "Hey, can I do X innocuous-sounding thing?"
Me: "Oh, um, sure, that sounds fine."
Player: "Just to be clear, X innocuous-sounding thing works in all circumstances, right?"
Me: "Yeah, I guess."
(at the table)
Player: "Okay, I do X thing in combination with Y loophole and Z, and it kills the villain instantly."
Me: "Wait, that's not how X thing works --"
Player: "But you explicitly said that X thing worked in all circumstances!"
Your question asks "are there any circumstances under which contracts don't work?" but omits to mention the specific circumstances you're wondering about. This makes me feel like you're trying to ask the question in a way that tricks us into giving an ill-considered answer.
I understand that you're writing your question under some constraints here, and you're probably trying to optimize for having a really short question. But the longer version you had originally didn't mention this exploit, either.