... and here are the links.
tl;dr? : the vendor assumes boiling of the wort.
Thanks for the update and links.
I was not aware of those threads/discussions. A bit of eye opener, LME fermenting in the dispensing/shipping bag...
From the little information I got on Williams' site, their extracts seem to come in at around 33 ppg, while Briess are 36 ppg.
I doubt those 3 points make all the difference in self-fermentation of the syrups or not.
However, bulk dispensing into bags may introduce contaminants...
10 years ago I used to get Briess bulk LME poured into thick doubled-up plastic bags from 30 (?) gallon vats at the brew store. Their bulk LME was never older than 30-60 days. Once, in the middle of moving houses, the bag sat at 74F room temps for 2 months before I brewed with it. It was definitely not fermenting in the bag. And yes, it got a full boil of course. Tasted great!
Now, the OP didn't use poured bulk extracts, he used LME
cans. Were they Briess?
I've seen those cans, from different maltsters, sitting on homebrew store shelves, some being well over a year old, and never saw one bulging or oozing or sticky remnants. Maybe those cans are sterilized or super-pasteurized?
From Briess LME bulletin (2021):
STORAGE AND SHELF LIFE
Store in a temperate, low humidity, pest free environment at temperatures of <90 ºF. Improperly stored extracts are prone to loss of freshness and color gain. May begin experiencing a slight flavor loss after 24 months.
Since the OP used factory canned LME, I think the odds of success are more in his favor here.
I certainly would not dump it now, unless things start to go badly downhill at some point. Keep an eye and nose on it, and see how it goes.
Sure, to the eliminate any chance of a possible infection from the unboiled extract, the OP can just re-pasteurize for 15' at 150F (IIRC that's the target time/temp target for wort pasteurization). Then chill as quickly as possible, aerate/oxygenate, and add new (dry) yeast. Or add liquid yeast if a starter is ready to pitch.