The active working dechlorinating chemical in all products is basically the same, either sodium thiosulfate, calcium thiosulfate, or some similar "thio" salt.
Some products add ammonia reducing agents, and other additions, as enhancers, but the dechlorination part is basic chemistry.
Because I was a water chemist/microbiologist, I never buy the fancy stuff, I just buy a bucket of dried sodium thiosulfate, and mix my own.
If your temp, or some other component such as pH was drastically different, or if the colder water was super saturated with gases, enough so, to cause gas bubble embolism. These are more likely the cause of a quick death, other than the dechlor