Well, perhaps not a typo exactly, although the Wikipedia definition says common usage of the word ‘typo’ extends to mean errors in grammar and word form.
That’s what we have here.
Take a look at the words on the labels of this (rather tasty) hot Belgian chocolate drink, made by Mars Drinks in the UK.
The photo above is two of the products on display which I saw today in Tesco in Reading. One label has the typo, the other is correct.
And it’s repeated in a photo in the product description online!
Do you spot the error? Whoever proof-checked the label before it went off for printing didn’t.