Becuase the Ex Post Facto Clause has existed for
Hundreds of years, Muniz did not create anything. The only that change was how Pa is (was forced to) interpret SORNA.
So one of the things that made SORNA punishment was that it increased your time on the registry. So, Act 10 removes that. However, you better believe Pa will make you finish your original sentence.
Also, the definition of anniversary means “the date which an event took place in a previous year.” An anniversary is not exclusive to weddings although it includes weddings. You can have the 4th anniversary since starting a job.