Hi. Context: 士道 and 十香 were talking about 折紙. 折紙 embraced 士道 and let go of him voluntarily. 十香 was surprised about 折紙’s behavior. Due to some reason, 折紙’s personality had changed a lot. 十香 thought 折紙 was not what she used to be because if the present 折紙 were the past 折紙, she would have sticked to /embraced 士道 persistently until 十香 forced to separate them.
Given the context, shouldn’t we use ままのはずだった rather than ままだったはずだ? The difference between the two expression is as follows:
「XXだったはずだ」 -- "it must have been XX" "I am sure it was XX" (as far as I can remember, XX must have happened or been the case, though what actually happened is contrary to my expectation)
「XXのはずだった」 -- "it should have been XX" "it was supposed to be XX" (but XX didn’t happen or wasn’t the case)
Do I get it wrong or this sentence is an exception? Thank you.
Please let me know if the context is not enough.