Transfer Function Error Wind Up, getting huge values from transfer function

Hello!

I am having a problem with a transfer function. The following function is part of a simulink subsystem, where i use the value leistungHS. This value is calculated using said function as well as read by this function. Therefore i needed to solve an algebraic loop (dotted red line showing the direct connection outside of the subsystem) using the transfer function on the left.

The function fcn works in different modes. In some use-cases/modes this works fine:

In one use-case/mode this leads to an error, where the function including its output as well as the input of the transfer function are working fine, but the output of the transfer function is windig up really fast and i am getting huge errors during these large values:

I tried using unit delay- or memory-blocks instead of the transfer function, but this doesnt work at all. The simulation is either very slow or just stops.

Is there a reason why the transfer function might behave like this (only in few situations)? What else can i use to solve the algebraic loop error?

Thank you for your answers!