JL063A HP M330 802.11ac Access Point - Cluster

[ago2503]

I've got two M330 (JL063A) Access Points, both on firmware V1.0.0.4-M330-B0019 and same hardware version R01. We're not able to form a cluster between those two APs. We setup one AP with all the settings we need, enabled the cluster and then tried to add the second AP with the quick-start. It always forms two seperate clusters with the same cluster name. It's like they don't see each other. Same subnet, same switch, they can ping each other, both IPv4. We meet all the criteria from the manual. We set the Syslog to debug and see that the clusterd is saying "informing that configuration has changed". Connecting via SSH and we see clustered=1 on both, cluster-ip=0.0.0.0, priority=0. Factory resetet both devices... no change. What am I missing here?! Thanks..