Orbi & Alexa - guest WiFi network issues

Alexa is enabling the guest WiFi network with my Orbi RBK53 set but:

 

- the guest wifi network is unprotected (accessible without password). I can enable the same guest wifi (without modifying its configuration) through e.g. Orbi web interface and then the guest wifi network is password protected.

 

- the guest wifi network enabled with Alexa skill cannot be turned off. I can ask Alexa to turn the guest network and I'm getting Alexa confirmation on this but the unprotected guest wifi network is still visible, accessible and with full internet access. It will not get disabled even after some longer period of time. The only option to turn it off is to enable the guest network through the web or app (then the unprotected guest wifi is replaced with protected guest wifi) and disable it the same way - web or app. 

 

My current config: RBR50 - router mode, no more routers, AP or managed switches connected to this network. Alexa is properly recognising the guest wifi network credentials - as I can see the wifi password in Alexa guest network enabling confirmation (Alexa on the android phone).