When native speakers encounter an unfamiliar phrase

Have you noticed that when native speakers encounter an unfamiliar phrase, they might distort their mental grammar to arrive at an interpretation they consider reasonable? This is common especially when they are reading English classics written a long time ago.

For example, in "I remembered also the nervous fever with which I had been seized just at the time that I dated my creation, and which would give an air of delirium to a tale otherwise so utterly improbable" from Mary Shelley’s Frankenstein, many, if not most, native speakers mentally add the preposition to at the end of the boldfaced phrase. They take it to mean "at the time that I dated my creation to," which in this context equals "at the time that I created the monster."

However, the preposition to in "date something to a time," if it were there in Shelley’s sentence, could not be omited without altering the meaning, not even in current English. But those speakers pretend it’s there and just omitted in order to arrive at the interpretation they prefer. The intpretation thus offered is not really reliable.

Should we take extra caution with native speakers’ judgments about the language in English classics?