Some cats like the "taste" and texture of plastic. More than likely, they won't eat it or swallow it, but just lick it and chew it. This is why it's best to keep plastic wrappers that could easily be swallowed out of cats reach. This is not uncommon at all.
my cat eats plastic as well. I have two and one will just play with things but the other definitely will eat it if I don't keep it out of reach or throw it away. At first I thought she was only playing with it until I found a piece of pink easter grass in the litter box one day. From then on I made sure to keep things away best as possible. But I also believe mine has an eating disorder. I rescued her from a friend who found her left alone in a house with out any food. All she wants to do is eat. She begs for food all the time. She will eat my other cats food if Im not careful. She has gotten so fat I am really not sure what to do. Anyway my point was she definitely will eat plastic along with most other things if I allow her to. But all cats are weird in their own way lol
There is something contained in some plastics that attracts cats to eat it (the name escapes me now and if anyone can remember it, I'd be thankful!) Our shop cat has a mania for packing tape and will even drag out the tape gun if we don't put it away properly.