Hello @OlivierCS,  Thanks for being part of this community.  I think this applies to https://issues.apache.org/jira/browse/NIFI-14841.  This looks like there are some issues known on NiFi 2.4 about load distribution.  According to the Jira, it's solved in 2.6.  Do you have this NiFi standalone or it's CFM? If standalone, you may take a look and consider using that newer version.  Maybe other members on the community have more ideas to share.   ... View more