I see +5/-1 on my end, seems like what you see is the opposite to Molten_Plastic, since his +v/-v count differed from the total post score whereas yours is the other way around.

I can’t replicate the issue, perhaps it’s just on your end?

No, MAC addresses are encapsulated at the link layer so twitter servers will never see it (exception being if you are on the same local network as a twitter server, since packets travel between many different nodes on the way to their destination, the MAC address will change between each pair of nodes)

Not exactly, they're recursively evil twins: Tim Cook is the evil twin of Tim Apple and Tim Apple is the evil twin of Tim Cook