Where it always comes up: we run into code that's either not compiling with #musl or compiling but then failing to do the right thing at runtime, because it's doing some convoluted nonportable dance in place of a direct and simple thing that would have worked on any system.
And the bad thing it's doing is a pattern that's somehow become popular, probably from a few major pieces of sw doing it.
And I want to say it's "cargo culted", but that term perpetuates a racist myth..