Responsa for Shevuot 82:13

Q. L asked A why he was occupying her property, since her husband had inherited the property from his father and she was about to take it in payment of her ketubah. A averred that he had bought the property from L's father-in-law, that he could produce the deed as proof, and that he could prove through witnesses a long period of undisturbed possession. A was then asked to produce the deed. The deed showed, however, that after the death of L's father-in-law, A bought the property from L's mother-in-law to whom the court had adjudged such property in payment of her ketubah. When A was asked to explain the discrepancy between his statement and the deed, A answered that he had bought the property twenty-three years ago and did not remember the details.
A. A's statement did not invalidate the deed, for a person does not usually remember details that are of no particular importance to him.
SOURCES: Cr. 311; Mordecai Hagadol, p. 309a.