The client probably have Direct Wi-Fi on and in use, and Meraki detects that and flag it as a rogue AP. This is a legitimate problem for some organization so its working as expected.
As for being labelled as rogue, if your Wireless > Air Marshal setting determines what Meraki will do when it detects this. By default, "Allow clients to connect to rogue SSID by default".
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CCNP Certified and Meraki Operator