A defiant IoT component is a smart device of an IoT system-of-systems (SoS) that should adapt its local behaviour to accomplish the new global requirements of the SoS only in exceptional scenarios. To handle defiant components, the current cautious adaptation solution, which relies on the use of AOP-based wrappers, may not be appropriate for IoT systems since the components expose their communication API. Therefore, this paper proposes a new cautious adaptation approach for IoT SoS that adds three external components, the Configurator, the Observer and the Effector, that realizes the MAPE control loop to apply behaviour adaptation. The solution is evaluated through a proof of concept using two types of IoT device communication mechanisms that demonstrated that our proposal helps the SoS to achieve its global goals.