Load balancing not working

I have a 3 nodes cluster(as you can see on attached images) with a connection with a Load Balance Strategy set to Partition by attribute, sometimes some flowfiles get stuck in this connection (see image1). Furthermore we have this log error in bulletin board

{{10:56:28 UTC ERROR xxxx-xxx-xx-nifi0.xxxx:8443 }}

Failed to receive FlowFiles for Load Balancing due to org.apache.nifi.controller.queue.clustered.server.TransactionAbortedException: Attempted to receive FlowFiles from Peer xxxx-xxx-xx-nifi2.xxxx for Connection with ID 0c20343f-f63d-1ef1-8da0-6d3cb9fc670d but no Connection exists with that ID
10:56:28 UTC ERROR xxxx-xxx-xx-nifi0.xxxx:8443

Failed to communicate with Peer xxxx-xxx-xx-nifi2.xxxx:8443 when load balancing data for Connection with ID c12f3c02-9f05-1232-ffff-fffff8d925a9 due to java.io.IOException: Failed to decrypt data from Peer xxxx-xxx-xx-nifi2.xxxx:8443 because Peer unexpectedly closed connection{}

The weird thing is that only some flowfiles are stucked other flowfiles goes forward in the flows.

I think this bug is the same of https://issues.apache.org/jira/browse/NIFI-9574, I post a comment in NIFI-9574 but I have got no answer.