Hi @Brash,
It would be very interesting to see what factors may be causing Splash page hits discrepancies between the networks;
(i.e. Do the networks displaying summary Splash Page statistics have a MX device while the affected networks do not?,
For the networks not displaying any Splash data, how many, if any, clients are seen connecting to the SSID when viewing Network-wide > Monitor > Clients, etc.).
If you have not already done so, I would highly suggest opening a Meraki support case, so that an agent could look into your specific network configurations and verify the backend reporting between the networks and Summary report.
To open a support case via the dashboard, please navigate to (?) > Get Help & Cases > Pick a Tile to Contact Support > Submit a case or by following the steps provided in the Contact Cisco Meraki Support document here.
Best,
Feli
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