I've seen all kinds of hybrids with them, which I blame on the government for allowing them in the first place. They should be BEVs only.
I did see a pure fossil with one too, thought it was pathetic they felt they had to lie like that - but I also see lots of cars with illegal plates with weird protuding letters, dodgy fonts, dodgy spaces etc - police don't care. I'm sure they'll pay the consequences sooner or later though, either through parking somewhere the ANPR can't pick it up (but a warden does), or failing their MOT and having to get the plates changed anyway.