Please help me, I don't know how to check next.

[MZSY]

I deployed a 3-node cluster in systemd mode, but when I looked at the status, I wondered why the three nodes had become one and two separate displays (I know the literal description is hard to understand).
When I query the member list of the cluster, the return value is as follows

You can see that the CLIENT ADDRS property of the etcd1 node has no value. I don't know whether this situation has any effect, but the following phenomenon occurs when I check the node status again, I don't quite understand

The return value is only the etcd1 node.
When I run the same command again, the return value is information about the etcd2 and etcd3 nodes

From the results, it looks like the cluster I set up is actually two small clusters, one with a single etcd1 node and the other with two etcd2 and etcd3 nodes, which is not what I expected.
What I want to know is which configuration file I should check in this case, because the configurations of the three nodes are almost identical, except for the ip and name differences

Please help me. I've been stuck in this place all day

[MZSY]

I have heard that it is better to have an odd number of nodes in a cluster, but I do not understand why three nodes are such a result