According to Hacham Ovadia Yosef there is a Halacha of Safek Berachot Lehakel meaning that in any case that there is one (or two I can't remember but it doesn't matter for my example) Posekim that hold not to bless on something we withhold. Why then by flavored gum do we make a Beracha if we have (at least three) Posekim that hold not to: Yaskil Avdi, Yishak Yeranen, and Birkat Hashem? There are probably more just not that I've seen.
Why doesn't Hacham Ovadia apply this rule over here?
In the Sefer Rivevos Ephraim 7:80:2 he holds that one makes a shehakol on gum because some flavor gets swallows and for thus reason one cannot chew gum on a fast day he also heard this from the Steipler.Then he brings a discussion from Rav Yitzchak Azuli from Yeshivas Porat Yosef who explains the stance of shu"T Yitzchak Yarnein and Yalkut Yosef which is that if one gets some sweetness and its for pleasure of the sweetness then one makes a shakol.see it inside for the back and forth.