4 pin POE over center pins?

Hello,

I just came back from a client site today after repatching a cable installed by one of the electricians.

After some investigation it looks like pins 1,2 and 7,8 are not terminating correctly to the patch panel which goes to a POE switch.

I am using t568B for reference.

I was surprised to find that when someone plugged a poe phone it worked with only 3,4,5&6 pins terminated.

My understanding of 100base cabling for POE used pins 1&2 for for Transmit and 3&6 for Receive.

If this is the case then the phone surely should’t even switch on let alone dial out.

My question is why/how does it work?

Thanks in advance to anyone who pics this up ?