This provision is called an attornment clause, and is routine, especially in commercial leases. As DaleM notes, despite the literal language of this clause, the duty to state that the landlord has fully performed, while drafted poorly (and if you can negotiate, it would be better to ask that the language be clarified to state that the tenant's duty may have exceptions if they exist), impliedly is limited to cases in which there is no breach. This implication flows from the general principle in contract law that one person's duty to perform a contract is usually conditioned upon the other party's non-breach of the contract. In cases where the Landlord has not fully performed, the tenant can respond by saying that the landlord has fully performed "except" in specified respects.
The purpose of an attornment clause is for a prospective buyer of the property to be able to confirm that there are no outstanding disputes with the tenants in a way that would be binding on the tenants as well as the landlord, or in the alternative, to learn going into buying a property that there is a present, active dispute between a landlord and a tenant under the lease even if it is not currently giving rise to litigation, so that the economic cost to the landlord of the dispute can be quantified when setting the value of the property at which the closing will take place.
Landlords include these clauses because if you can't obtain attornments from all of your tenants, your property is virtually unmarketable as a matter of commercial reality, and at a minimum would sell for a much lower price. I have had clients refuse to buy buildings because the selling landlords couldn't produce recent attornments from their clients.