I am experiencing a similar issue in our Wlan.
We have a single SSID that supports several (3) iot user profiles. 2 of the user profiles seem to operate without issue. A third user profile will intially authenticate (via PSK) and receive a valid IP address. The device operates as expected. Randomly, the devices will loose connectivity with the internet (while still connected to Wlan network)
Rebooting the device often re-establishes a valid IP address and connectivity to the internet. Users are becoming frustrated and I am desperate for a resolution........