GeoNode has some quirks when it comes to handling metadata. It stores some fields in its backend database and it stores a full XML metadata document in the database if you specify that you don't want to be able to edit the metadata after upload. While the metadata supports some GeoNode content it also has to be available for search and query via the CSW endpoint provided by the pyCSW service that comes with GeoNode.
GeoSAFE added further complications: Firstly that metadata had to store InaSAFE keywords in a non-standard 'nested' XML document within the main metadata Supplemental Information element; secondly, that the metadata document has to sit with the exposure or hazard data file (typically shapefile or GeoTIFF) on disk, i.e. outside the database.
If you edit the metadata it has to be maintained in at least two places, not lose any content and not break anything.
We've made various fixes that make metadata upload, replacement and editing more reliable and predictable.
https://github.com/kartoza/geonode/issues/396 https://github.com/kartoza/geonode/pull/500 https://github.com/kartoza/geosafe/pull/378