Snapchat's 'disappearing' videos don't actually vanish
money.cnn.com
2 threads
This doesn't really seem like a privacy breach on the part of Snapchat since it's your own device that is the "culprit", it is more of a feature of iPhones than a flaw of Snapchat's.
Also, there are many other ways to "cheat" the Snapchat timed delete of videos and pictures, eg screenshot or recording with another device.
No this is on the other person's device.
You'd think they would flush the cache.