Can a lender be held liable for negligence if a document is found to be defective or missing?

I agree. At some point the line of contributory negligence may be crossed by a lender's failure to discover an obvious defect or, as in Doiron, a missing document. But to find that a lender must minutely examine documents with a solicitor's eye would have the practical effect of dispensing with the necessity to hire solicitors in such situations. Surely a lender, even a sophisticated lender, does not have to meet that onus. As LeDain J. said in Central Trust v. Rafuse et al.(October 9, 1986, as yet unreported [now reported 1986 CanLII 29 (SCC), 31 D.L.R. (4th) 481 at pp. 529-30, [1986] 2 S.C.R. 147, 37 C.C.L.T. 117]): [The officers and directors of the lender] did not have a duty of care with respect to the legal aspects of a transaction other than to retain qualified solicitors to perform the necessary legal services ... and quite properly left the legal aspects of a transaction to the retained solicitors.