r7800 wifi 5ghz 2.4ghz isolation

R7800 with Voxel .77 firmware. Guest network is disabled. I have a couple of devices on 2.4ghz wireless (ex: wifi light switch) that can't be reached from devices on 5ghz wireless. I can reach them from wired devices. When my cell phone is on 5ghz, I can't reach the devices but if I move out...