The MCAS may not have been designed as an anti-stall system, but that doesn't necessarily mean it functioned according to design. The possibility for multiple activations integrates the control response, converting feedforward control into a closed loop (it will continue to act on the trim until the AoA decreases). Somewhere a decision has been made about a control system without requisite knowledge or understanding of the consequences, and this made it through design validation, testing and certification. That is highly disturbing, as there is no certainty that MCAS is stable in any circumstances where the pilot is making manual trim adjustment.