Akka Cluster connection error

I have the following error when starting akka cluster in kubernetes, only with akka version > 2.4.16. Can anybody help me with this pls ?

[DEBUG] [03/27/2018 16:56:13.362] [New I/O worker #4] [NettyTransport(akka://InvoicesClusterSystem)] Remote connection to [/172.17.0.1:52788] was disconnected because of [id: 0x9426620d, /172.17.0.1:52788 :> /172.17.0.4:2552] DISCONNECTED
[DEBUG] [03/27/2018 16:56:13.363] [InvoicesClusterSystem-akka.remote.default-remote-dispatcher-7] [akka.tcp://InvoicesClusterSystem@invoices-seed-0.invoices-seed:2552/system/transports/akkaprotocolmanager.tcp0/akkaProtocol-tcp%3A%2F%2FInvoicesClusterSystem%40172.17.0.1%3A52788-10] Association between local [tcp://InvoicesClusterSystem@invoices-seed-0.invoices-seed:2552] and remote [tcp://InvoicesClusterSystem@172.17.0.1:52788] was disassociated because the ProtocolStateActor failed: Unknown

$ifconfig

docker0: flags=4099 mtu 1500 inet 172.17.0.1 …

$kubectl get po -o wide

NAME READY STATUS RESTARTS AGE IP NODE

invoices-seed-0 1/1 Running 0 19m 172.17.0.4 minikube

invoices-seed-1 1/1 Running 0 19m 172.17.0.5 minikube

kubernetes - v1.9.0

Any more hints in the log before that entry? (also, check on both the joining and the existing node)