Spotfire currently doesn't validate whether all objects related to the folder have been exported successfully. Also it doesn't log on the list of objects exported successfully in the impex.log file. Due to this, when we execute the export using command, we have observed that certain objects are missed . It's causing issue during import on target server as the object is missing in production. Issue reported on the support case 01621029 for your reference.
If you enable debug logging for the impex.log log file, you'll get a log entry for each element being exported. Perhaps that could help for know.
To enable Debug logging for just the impex.log, please open log4j2.xml in a text editor and change "INFO" to "DEBUG" in the section mentioned below.
<Logger name="com.spotfire.ws.library.IMPORT" level="INFO" additivity="false">
<AppenderRef ref="impexlog"/>
</Logger>