If you do a simple search on this product, you will see lots of bloggers jumping all over it as an example of ignorant English usage. English misuse is commonplace in Japan, but this is not such a case. The name might or might not be a good marketing move, but there is a clear reason for choosing it. This photo is of an empty bottle. Kirin Afternoon Tea, The Pungency キリン、午後の紅茶
There is the definition for from Twinnings USA tea glossary
Describes a preponderance of desirable attributes, which are the essential characteristics of a good tea. Pungent describes a tea liquor which has a marked briskness and astringency without being bitter on the palate. A most desirable cup characteristic.