When people join my server after changing my name, their data gets wipped and another uuid is created for them instead of the one created before changing their name. I have seen other people have the problem on their servers and it's not to do with my plugins/server.
Someone has made a fix but I suggest if mojang want their community to stay in minecraft then they should fix this issue, some players don't want a extra plugin due to the fact their server could be lagging now because of too many plugins.
Mojang is not responsible for servers.
https://mojang.com/2015/01/announcing-minecraft-name-changes/