GS1200-8 vlan behavior on incoming tagged frames

Hello. I want to buy the device in the title. Before that I would appreciate it if someone could help me understand the following expected behavior:

If I configure for example port 1 and 5 with vpid 10 and port 2 and 6 with vpid 20, it is my understanding that when a host connected to one of those ports sends an untagged frame, it is wrapped with the vlan id of the port so that a forwarding decision can be made, and only the ports with that same vpid will be able to see the packet (please correct me if I'm wrong).

However, let's say I connect a host with a vlan capable nic to port 1 and configure the host to send frames with tag 20 (different than the port's vpid), will the switch either:

1.reject the packets.

2. Remove the tag and put a tag for vlan 10, then proceed to forward to ports with vpid 10 only.

3. Accept the vlan tab of the packets and forward them to vlan 20 ports, even if the receiver port is not on that vlan.

Option 3 is dangerous for my use case and the behavior is not clear to me from reading the documentation.

Thanks.