HA Setup - Active Passive

Ok everyone, I am trying to get back to our HA setup and have a few questions. We have 2 X XGS3100's, the Primary unit is active and currently registered and subscribed. I fired up the second 3100 today...
HA active-passive preferred primary device

Documentation says for HA active-passive you should select a preferred primary device, because " only the initial primary device holds the licenses and supports services, such as FastPath offloading. ...
XG210 upgrade to XGS2100 in HA active-passive configuration

I have a current setup with a pair of XG210 in HA Active-Passive mode and am preparing to upgrade them to XGS2100 in the same HA configuration. I have a configuration backup from the active XG210 and have...
v21 HA Active passive - Aux node fails - system startup failed - fault state

I have a HA cluster where it happens now second time that the Aux node was not able to join the cluster or went into fault state after a time of Primary node being down. First it happened while HA initial...
XGS2100 with SFOS 20 GA - blocks UDP 500/4500 from WiFI2WAN or from LAN2WAN

Now the XGS2100 HA Cluster (SFOS 20 GA) also suffers from the same problem as the XG125 Rev.3 (SFOS20 MR2) and the XG115w Rev.3 SFOS20 MR2). The firewalls start blocking UDP traffic on port 500/4500...