1739. A buyer who ascertains that the property is defective may give notice in writing of the defect to the seller only within a reasonable time after discovering it. The time begins to run, where the defect appears gradually, on the day that the buyer could have suspected the seriousness and extent of the defect.
The seller may not invoke tardy notice from the buyer if he was aware of the defect or could not have been unaware of it.