I'd like to understand why a summoner's PUUID changes when I thought it was unique for each account. I'd like to understand this because I'm developing an application where I need to retrieve data from LEC players, but if I use summonerName the name is likely to change, and if I use puuid it changes too, so I don't know what I can do to automate the retrieval of an account.
The puuid is definitely unique, but is different when you use a different api key. That's to prevent you from using multiple keys for the same project.