Art. 34 CISG
If the seller is bound to hand over documents relating to the goods, he must hand them over at the time and place and in the form required by the contract. If the seller has handed over documents before that time, he may, up to that time, cure any lack of conformity in the documents, if the exercise of this right does not cause the buyer unreasonable inconvenience or unreasonable expense. However, the buyer retains any right to claim damages as provided for in this Convention.
The Secretariat Commentary on Art. 32 of the 1978 New York Draft, predecessor to Art. 34 CISG, gives insight into the drafters' unterstanding on the eve of the 1980 Vienna Diplomatic Conference.
Overview of case law on Art. 34 CISG: UNCITRAL Digest
The UNCITRAL Digest on the CISG can be used as a starting point to discover the relevant case law on this article.