I am reading Kanon, I will first give the context:
[Generally,] Since when did we start eating Japanese food for breakfast...
The main character then narrates:
Until yesterday, I have unmistakable expectation that it was toast and boiled eggs
If the expectation was until yesterday, should it not be 「だったはずだった」? He surely no longer has the expectation since he has just had his expectation contradicted. My belief is either I am confused at what the copulae are referring to, or 「までは」 forces the rest of sentence into the past (so the plain copula is present tense... in the past... (time travel tense trouble))