Pose Mastery
It’s not broken, it’s a custom
You are confused it seems. Folk aren't asking for cartoon accurate, they are asking for lore accurate. We already have official realistic depictions of phase 1.5 helmets and the differences in design in the cartoon series were intentional design choices (p1 ears, diamond chin, sharp ridges etc) as it is supposed to be a blend of p1 and p2 helmet, basically the prototype of phase 2. To miss out almost every detail that makes a p1.5 a p1.5 means it loses its identity. What HT have made is a phase 2 helmet with a fin. The absolute laziest Hasbro style move possible.
These figures are repaints of the Umbra Arc Trooper. So HT did not change the mold. Who knows maybe they will replace the mouth piece before release like they did with Vaughn.
Dice also didn’t have the ears correct so the design varies it’s not just HT getting it wrong. Sorry you’re held up on such small details.
Designs are made for shows not for lore. That’s why they are different in every show.