There are cases where things were discovered in multiple places, but that's usually the result of multiple groups having success at around the same time - and the groups know about each other. One group discovering X and then several years another group discovering X independently is very rare as that would mean they didn't talk to each other for years or the second group doesn't know what's happening in their field. That does occur for nuclear weapons and other sensitive technology, but it's very unusual otherwise.

https://en.wikipedia.org/wiki/List_of_multiple_discoveries