The fight is over a fork, a copy of an open-source project that someone else takes in a new direction. Anbernic’s promotional videos show the RG DDS running 3DS games on AzaharPlus, an unofficial version that isn’t part of the Azahar project.
The two differ in an important way. Official Azahar was built so it doesn’t get around Nintendo’s encryption itself. You have to supply game files that have already been decrypted, usually by dumping them from your own 3DS with a homebrew tool called GodMode9. That keeps the official project at arm’s length from piracy, but it’s slow, and dumping a big library can take days.
AzaharPlus skips much of that hassle. It has a decryptor built in, accepts files that work with older versions of Citra (the 3DS emulator Azahar descends from), and can download system files from Nintendo’s own servers. Convenient, yes, but it also makes it far easier to play games you never owned.
The Azahar developers have a second complaint. AzaharPlus kept the Azahar name and uses a similar logo, so many people can’t tell the two apart. Azahar developer PabloMK7 tried to get the fork’s maintainer to rename and rebrand it, but that request was reportedly refused. Another emulation app, Cocoon, had already said it would work only with official Azahar.