Yes, it is, but multiple orders *over the same amount range* are redundant. The taker code simply drops all but one of them, so in this case, the maker gets no advantage from it. It is irritating, because it spams up the message channel, but apart from that, it's not harmful.
Thanks for the clarification. I have seen a drop in number of coinjoin transactions entered into by my maker bot. I just wanted to make sure that is not due to these multiple orders and that they have no advantage over others.