If you are using VLANs, you likely have little need for the port isolation feature.
Yeah I agree that is not necessarily needed but it would be like an extra pseudo security to isolate ports and members of VLANs, gives you more control on network.
What exactly breaks (so I know what to test)?
In my use case I'm using something like this:
Port 1 -> Just for managing switch and this port is isolated from all other ports.
Port 2 -> Trunk port with 2 VLANs (100 & 200) both VLANs have DHCP servers.
Port 3 -> Untagged with Default VLAN 100, connected to a computer for using VLAN100 Network.
Port 4 -> Untagged with Default VLAN 200, connected to NVR for using VLAN200 Network.
Port 1 -> Fully isolated
Port 2 -> Access to Port 3 & Port 4
Port 3 -> Access to Port 2
Port 4 -> Access to Port 2
VLAN 100 -> Port2 & Port3
VLAN 200 -> Port2 & Port4
as I said before when there is no port isolation and all ports can access to all VLANs it works perfectly (DHCP work and can ping devices), but with limitations it breaks and VLANs don't work at all (DHCP doesn't work, even with static IP can't ping devices).
Thank you in advance.