Pablo, the model you shared sounds like it shows a different phenomena than what you were describing in your initial post, as when I follow your instructions I receive “Attempt to access a non-direct-feedtrough input signal” instead of an algebraic loop warning.
From the C-Script component help: “An input signal has direct feedthrough if you need to access the current input signal value during the output function call. This has an influence on the block sorting order and the occurrence of algebraic loops (see Block Sorting).”
If you use an input signal in an output function, then it would be by definition be a directfeedthrough signal, which generates this error.