I work at Starbucks, a few months ago the SBUX vanilla syrup lost the kosher certification,
Also for all Frappuccino’s, the frap roast is kosher but the frap base (which is a necessary ingredient that cannot be removed) has never been kosher by any certification
And what are the ingredients of the syrup?
If it includes meat, chicken, fish, cheese or grape juice/wine, then it would need a kosher certification. Otherwise, it’s pretty much inherently kosher just as a cucumber doesn’t need kosher certification to be kosher.