Transient simulations in FEFLOW that have an outer iteration in the solution for each time step (non-linear equation system, e.g., due to a phreatic surface) do not stop if the outer iteration does not reach convergence in a single time step. Instead of halting the simulation, FEFLOW throws a warning message in the log window, showing the time and the residual error in this time step. It is up to the user to decide whether to accept the simulation results or not. Like in your case, convergence problems often occur in the very first time step when the initial conditions are far from the expected result.