Yeah it's pretty much exclusively used incorrectly. The original meaning was that an exception to a rule proves that such a rule exists. For example, "no parking on Sunday" is an exception that implies that parking on any day except Sunday is okay.

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

It honestly doesn't bother me as much as when people incorrectly say "begs the question" when they mean "raises the question" but I think we're long past the point of us ever correcting any of these.