Lessee knows of the defect at conclusion of the contract or upon acceptance

If the lessee knows of the defect when concluding the contract, then they do not have the rights under sections 536 and 536a. If the lessee remains unaware of the defect due to gross negligence, then they have these rights only if the lessor fraudulently concealed the defect. If the lessee accepts a defective thing despite being aware of the defect, then they may only assert the rights under sections 536 and 536a if they reserved their rights at the time of acceptance.