There are many products that have different seasonal variants for different times of the year. Some products are even only available during the said reason.
These "seasonal" products seem to also be great opportunities for companies to try out new flavours. If it's a flop they can easily fade it away at the end of the season and just never bring it back.
Sometimes it's a shame if a product ends up being my new favourite. First there is the worry that not everybody feels the same and it's never coming back. And even if it sticks then there is almost a whole year to wait for it coming back to shelves. At least they stay on sale for several months before, and sometime after as well so there is enough chances to get enough of it for the meantime.
But it's not always guaranteed that the next year the flavour will be exactly the same. There is always those "new, improved recipe" cases when it's actually not even em close to the original taste. What a disappointment after waiting for almost a year to once again being able to enjoy your favourite.