That’s strange, I’m seeing the same behaviour when trying to open my own HDF5 files (also generated with HDF5.jl) using HDFView 2.11.
I’m guessing it’s an HDFView issue, as other tools such as h5ls work as expected on the same files. Maybe the HDFView version is too old, and can’t open files generated with recent HDF5 versions? Note that there is also an HDFView 3, but it doesn’t seem to be that easy to install on common Linux distributions.