"So what does it mean that the TP-Link has issues?"
Ports can not be removed from vlan 1.. Any broadcast traffic on vlan 1 will be seen on ALL Ports not just vlan 1 ports.. So if you have broadcast traffic on vlan 1, all your other vlan will see this traffic..
I have the same issue on a TP-Link access point. As a result, IPv6 router advertisements are appearing on the wrong SSID, causing devices to get an address on the wrong prefix. While other TP-Link switches may be OK, I think it's better to just stay away from any company that does things that are so incompetent.