Hello, at home I have a Ex233v router in an Easy Mesh setup with two 705X extenders.
Everything works well, there is just one wifi network all over the house and, even though the Ex233 is an ISP-provided one, the Mesh feature works very well.

Today I enabled (for the first time) the Guest Network on the router (I needed to give temporary access to a person). While the Guest Network was on, this guy was able to surf the Internet, I could continue working too (my laptop is connected to the EX233), but all the devices connected to the two range extenders went offline.

Checking the router's webpage, both extenders were still shown as connected to the router, but their webpages/IP addresses were actually unreachable.

In fact, I took my smartphone to the back of the house, where one of the repeaters is located, and as soon as the phone connected to the RE, I lost the Internet connection (it came back as soon as I walked back into the dining room, where the router is).

Rebooting both extenders twice didn't help.

As soon as I disabled the Guest Network on the router, both extenders started working again immediately (see the screenshot below).

Am I missing something here? Is this a normal behavior?