I just used the UTM5 grid and noticed the geometry type is 'unknown' (rather than polygon), which can cause issues with some tools (in my case Django's Layer Mapping tool).
As a workaround, I was able to generate a "better file" by importing in QGIS, then re-exporting the layer to a different GeoPackage.
It might be better to update the file directly here on the repo (and also check if the other grid file suffers the same issue).
I just used the UTM5 grid and noticed the geometry type is 'unknown' (rather than polygon), which can cause issues with some tools (in my case Django's Layer Mapping tool).
As a workaround, I was able to generate a "better file" by importing in QGIS, then re-exporting the layer to a different GeoPackage.
It might be better to update the file directly here on the repo (and also check if the other grid file suffers the same issue).