Why WiFi icon is showing up in top bar after off

IdrisSeabright wrote:

You can't turn WiFi off from the Control Center. Tapping the WiFi button in the Control Center disconnects you from the WiFi network you were connected to but leaves WiFi on. If you want to turn off WiFi, go to Settings>WiFi.

Still, with Wi-Fi toggled off in Control Centre, the device shouldn't stay connected to Wi-Fi.

Use Bluetooth and Wi-Fi in Control Center

Disconnect from Wi-Fi networks

Open Control Center on your iPhone or iPod touch, or iPad and tap the Wi-Fi button . The icon dims and your device disconnects from any network that you're connected to.

While Wi-Fi is disabled, auto-join for any nearby Wi-Fi networks is also disabled until:

You turn on Wi-Fi in Control Center.

You connect to a Wi-Fi network in Settings > Wi-Fi.

You walk or drive to a new location. 

It's 5 AM local time.

You restart your device.

You can't turn WiFi off from the Control Center. Tapping the WiFi button in the Control Center disconnects you from the WiFi network you were connected to but leaves WiFi on. If you want to turn off WiFi, go to Settings>WiFi.

If you go to Settings > Wi-Fi, does it show that you are still connected to the Wi-Fi Network?

If yes, possibly some glitch. Restart your iPhone and check again.

Restart your iPhone