Is it unusual for zoas from the same frag to have slightly different coloration? I ask because you can see in the picture only one has the orange center.
The 4 polyps near the bottom are all relatively new growth from the frag that has been in the tank for several months. Could a different type of Zoa remain “dormant” for months?
Some zoas (most notably hallucinations) change as they mature. It’s not unusual for new polyps to look different from the rest of the colony, this is especially common in fire and ice strains.
It’s likely just an immature polyp however, it’s possible they might be morphing slightly. Time will tell.