Answer to your questions:
1) Has this ever worked correctly or at least better in this environment / os release / patch level , Cloverleaf release / patch level? YES. It has been working correctly for years
2) If this behavior is consistent across all connections and sites, perhaps something has changed at the network level – have there been any changes to any software modules or configuration related to networking / ip / hostnames? YES. All sites have the same issue with connectivity.
3) Is DNS or the equivalent functionality on Linux configured correctly? please forgive my incomplete knowledge, but could this be one of those problems relating to a timeout looking for a network definition? That is what i am having our network team looking into if i can get them to do it.
4) is the Local Binding Addres correct and recognized by the network configuration? Not sure.