Yep, that’s right. It is how Dgraph works. If you add a new Alpha you have to increase the replication factor too. Not just add more nodes. If you add more nodes in a replica 3 factor. And you already have 3 Alphas. Dgraph will create a new group. If you still want to replicate you have to alter the replica factor along with adding more nodes(Alphas).
The math is like replica factor / number of Alphas. If your replica is set to 6 for example. And you have 3 Alphas. The cluster will expect that you add more Alphas later until reach 6.
If you have replica set to 6 and 18 Alphas you have 3 groups.
In short, in order to scale you need to alter the replica factor too.
For this case you should use “remove node” before anything. And also not reuse the RAFT ID. You may just have messed up with your RAFT context. Just shutdown the cluster and delete all Dgraph directories in there.