So everything has been working fine until today after adding more backend server.
If i run the configuration with all the servers in the list csv will start showing blank after doing checks on all servers. But if i do removed two backends server ( doesnt mather what servers or in which backends ) in the configuration csv will work without any problems, i have the same configuration on another server ( master ) and there is no csv stats blank problems when having all the backends servers in the configuration.
Please note that normal html stats page works and i can se all the information, it is just the CSV stats that goes blank: http://x.x.x.x/;csv;norefresh