I have been learning the most recent OpenGL techniques by making a Quake 2 Renderer. I am having an issue using a sparse texture 2d array. I have the code up on github here: discoloda/Quake-2 · GitHub in ref/gl3/texture.cpp, the pertinent bits are Manager::Storage and texture_get_managed.
The first attachment is where Sparse is enabled, the second is where sparse is disabled.