Please, show me an issue with 8.1 that is solved by using the legacy branch and not user error.
I've got one. It's called booting a 9.2 EmuNAND. Legacy can do it. Luma 8.1.1 cannot.
Unless you make all EmuNANDs on the card minimum size, 8.1.1 crashes launching a 9.2 EmuNAND every time. And doing that breaks compatibility with Cakes and ReiNAND, as opposed to just making the last one a minimum sized RedNAND, while making the rest legacy sized, which is the most compatible option. I've got Puma working with B9S so I can boot 9.2 without wiping my configuration by launching Legacy. So, it's not really impacting me, but you asked for an example, so supply one I have. It is a genuine issue that is not caused by user error.
As for why I'm setting up a second EmuNAND to run 9.2 (aside from Menuhax being a fast homebrew menu launcher, and just because I can), well, *hax still isn't working in 11.5 or even 11.4 on the O3DS (which my SysNAND and first EmuNAND are running, respectively, and while the 11.4 is partial for obvious reasons, it probably still breaks *hax all the same). And as for why I still need *hax, Rosalina still has problems with:
3DSCraft: garbled graphics
ctrHexenII: crashes
ctrQuake: crashes
ctrWolfen: exits to the menu when you pick a game
eDuke3D: crashes
Spectre3DS: console not visible when entering "map start", garbled graphics and an endless stream of "WaitForEvent timeout" errors once game has been properly started
I'm not overly concerned about those first five, but Spectre3DS is Quake in true stereoscopic 3D. There's no menu yet, and you have to use a console command just to start the game, but it's still an impressive port overall.
Its my fault for not bringing any of this up. Honestly, it was considered to be one of the reasons as to why I kept switching to the legacy version of luma 7.1. Now that I think about it, I could have sworn there was a post saying that not all the homebrew files can work with it. This piece of information was buried within the first luma discussion thread. Maybe i'm seeing shit.
Well, you're the only one that can know what you are seeing, so you must decide whether you're seeing shit or not. But as far as homebrew not working, just look up.