At time T, you have signal going into Subtract. Subtract is instant, so at time T, the result of Subtract is going into Switched Derivative and also going through through. Switched Derivative is instant, so at time T, the two values are going into the fuzzy controller. Fuzz controllers are instant, so at time T, there is output based upon that input signal.
Now the output of the fuzzy controller is at time T, and it is being routed back to input of Subtract, still at time T. But if that result was different than whatever the value was on the line at the time that the Subtract started, then that would lead to an inconsistency.
To avoid a problem, Simulink needs to look through all of the internal parameters of the items in this loop and try to tweak the parameters and initial conditions so that no matter what the signal is at time T, that Simulink is able to fix up the initialization so that there is no inconsistency.
Unfortunately for you, Simulink cannot figure out how to initialize all the possible parameters in such a way that there is no inconsistency.
Now, if only one of those blocks was not instant, then the looped-back item would not be arriving at the exact same time as whatever was there before...
