Triacetin is an ingredient in things like TFA smooth and Vape Wizard, and is used in such tiny quantities of mixes that it's hardly there...
for instance, if you use TFA smooth, you'd normally use it at a half a percent of the mix, and triacetin is only a small percentage of Smooth, so the amount your getting is very small..
As such, and as it's FDA approved as food safe, I don't see it being an issue at all..I've never worried about additives as a result.
Cinnamon flavoring and other additives was known to crack plastic
tanks in the early days of
vaping, but I believe that was a reaction between the type of plastic used back then and some flavorings..it doesn't seem to be an issue with modern or more recent plastic tanks.
I don't recall triacetin having that issue, but it could just be my memory..
At any rate, there are millions of long time vapers who have never had any lung issues, so I don't see that changing..
the recent spate of lung illnesses was due to vitamin e acetate being added to illicit THC products and not nicotine e-juices..so no worries.