PHEV’s are getting reclassified/re-regulated by the EU, because:

• The stated average emissions are based on actually plugging in to charge, which most owners don’t bother with, considering electric propulsion only accounts for like 1/15 of the cars total range
• It has been regulated in a way that gave the manufacturer only small emissions penalty for increasing the motor size & weight of the car - because it was still considered to be electrically powered.
• The design itself leads to a heavier car (having 2 propulsion systems)

Meanwhile, the full EV market has been more self-regulating in the sense that they have kept the weight/energy requirements down in order be competitive on range.