Hi,
Before disabling Aruba Instant GUI in Group>Basic page, make sure those devices are in monitor only mode.
If you added devices in manage mode and disabled the instant gui, Airwave will push default group template which might not have complete configuration.
We could run below db command to check whether device are in monitor only mode or not.
Note: commands only work below 8.2.4 version.
#dbc "select count(*) from ap where monitor_only = 1";
Regards,
Pavan