If FGDC metadata hasn't been upgraded and it has elements corresponding to the item description that contain the & or < characters, the metadata can't be displayed.
Upgrade the FGDC metadata to ArcGIS metadata with the Upgrade Metadata tool using the FGDC_TO_ARCGIS upgrade type. This tool is available from System Toolboxes (or ArcToolbox) > Conversion > Metadata > Upgrade Metadata.