rly tx clients <path> is supposed to create a new client on both chains. HOWEVER if you have if you already have a client-id in your config associated with that path, the command will not create a new client.

For example if you config looks like:

paths:
    demopath:
        src:
            chain-id: ibc-0
            client-id: 07-tendermint-0
        dst:
            chain-id: ibc-1
            client-id: 07-tendermint-0
        src-channel-filter:
            rule: ""
            channel-list: []

And you run
rly tx clients demopath
A new client is not created.

AFAIK the --override flag is supposed to override you config and create a new client.
This does not work.

The only way to create a new client is to remove the client-id from your config and re-run command (--override flag is not necessary):

paths:
    demo:
        src:
            chain-id: ibc-0
        dst:
            chain-id: ibc-1
        src-channel-filter:
            rule: ""
            channel-list: []

This is posing issues for client related tests in ibctest