Management-only means that it will still accept traffic for management purposes on that interface. It will not route traffic from the management interface towards other interfaces, and vice versa, however, the interface itself if it's part of your internal network, it will still accept management traffic (ping, telnet, ssh, http/https access towards the interface).
When you say that it's attempting to route traffic, what do you mean by that? As far as routing is concern, once the interface is enabled/up, it will still be accessible if it's part of your internal network.