I bought this device because I wanted to set up a separate, isolated network for my guests. I can set up a guest network but it is not isolated from the rest of my LAN and that beats the whole purpose of setting up a guest network in the first place.

Even with 'Allow guests to see each other' and 'Allow guests to access your local network' ticked off, I could for example happily cast something from a device on the guest network to my chromecast on my main network, or access the NAS.

The behaviour is the same in router mode and in access point mode and I'm on the latest firmware.

I've been googling and found that this issue was flagged before in this thread: https://community.tp-link.com/en/home/forum/topic/168548?sortDir=ASC&page=1

TPlink is aware since a long time and thus I can only conclude and confirm that it is a mislead and false advertising to the customers.

Needless to say I'm returning this device and go look for another brand that handles a guest feature or vlans correctly.