I would recommend having the user/IT personnel test this at the location, and calling Support to troubleshoot on the call. They could take a look at the logs and where the destination traffic is heading to/from. Taking a closer look at their documentation, they put this disclaimer for all it's worth:
Note: File sharing programs, such as BitTorrent, are now able to be configured to encrypt traffic as secure HTTPS, potentially bypassing P2P traffic shaping rules that have been configured. Cisco Meraki MX Security Appliances and Wireless APs are capable of detecting some of the encrypted P2P traffic on the network. When encrypted P2P traffic is detected, it will be matched to any configured P2P traffic shaping rules, and honor the limitations that have been configured. However if the traffic is encrypted, it may not be possible to accurately classify all of the offending traffic.