No. Did you find out it was fake news? I do see the story was picked up by Daily Mail and NY Post so it could be that the BBC didn't fact check, but they're usually pretty good.
I'm still more concerned about what I mentioned - McDonalds working conditions. It'd be hard to breathe in a steamy kitchen standing over a deep fryer. How effective would a mask even be in a greasy humid kitchen? Maybe someone took it off and had it hanging off one ear for a second and it fell in. Maybe an ear elastic snapped or came unstapled (happened to me with a couple of the blue paper ones - elastic came unattached), and fell into the deep fryer while they were hustling to get orders out as though it were an ER. At least, regarding germs - it was deep fried in hot oil, and so disease wouldn't have been the hazard. Choking on it would be the danger, though.
How likely is it that someone would get covid from a littered mask? Probably just as likely from a littered cup or straw.
Think of how McDonalds plastic garbage has been filling up landfills and how much garbage gets strewn about in general. At least paper masks will eventually break down, won't they?