Could this be related to announcements that were planned for E3?​

California man who hacked into Nintendo servers to steal video games and other proprietary information pleads guilty Seattle – A 21-year-old Palmdale, California, man pleaded guilty today in U.S. District Court in Seattle to federal crimes related to his computer hacking scheme and his possession of child pornography found on his digital devices, announced U.S. Attorney Brian T. Moran.

So a weird situation has been developing over the last few days in certain Nintendo circles. First, screenshots of what appears to be an internal build of Flipnote Studio appeared. According to the person who first posted them on a private Discord, they were obtained from Nintendo servers.According to another screenshot from Flipnote Studio, it was supposed to be revealed at E3, there is a comment dated June 10, 2020.Now, music tracks from Pokémon DLC #1, to be released in June have started leaking:If this is true, it would not be the first time Nintendo internal servers got hacked and info leaked, as in 2016 a person hacked Nintendo servers and obtained info about Nintendo Switch before its release:I would not be surprised if more leaks appear in the following days...