The Pandora FMS agent sends data every time his interval is fulfilled, knowing this we will take as example a 5 minutes interval. If after an interval we observe that more than one XML with the same agent name arrives, it could be due to different causes:
xml_buffer . If we have configured this field to 1, the XML generated by the plugin and cannot be sent to the server because of some problem, they will be stored and sent in the next execution when it is possible. So if you receive several XML from the same agent could be old XML. Some versions ago there was a bug that the buffer sent all the time the XML and did not delete them (to discard this error update to the most current version).
Queuing in the server processing. This cause is because the XML of that agent or others have been queued because the server has been down or has too much load. This causes files to be left unprocessed and therefore accumulate to a large number depending on the number of agents. To solve this, you can increase the number of threads in the data server and restart it, delete all these queued XML files or move them to another folder and send them to the data_in folder gradually. As last option in recent versions you can temporarily enable the dataserver_lifo token in /etc/pandora/pandora_server.conf .
data_BADXMLXML . If the format of the agent XML in the server has this format it indicates that the generated XML is badly formed. It can be due to characters that do not have the same encoding of the agent or any other problem. To debug it you can use the xmllint tool on the badxml file and it will indicate the line where it is failing.