replacement node won't join cluster anymore

Yes, we sure did. And according the strange messages within the logs we've decided to make a new install on the master node and setup HA again. At this moment Failover and sync is stable again. However, the master node has also a LLC module. Somehow we can't get the LLC config on the replacement node. We even tried to recreate all settings from scratch, but there's a bug preventing us to make a selection of a VS. Therefore we tried to pull the settings from the master node with the "gtm_add" script. But this fails at some stage on a SSL cert failure. Then we tried to import the certs on both nodes but without an success this far.. I think we're going to create a case with F5 next business day.