**Affected version:** 8.2 - 8.5.2
**Fixed in:** 8.5.3

### Problem Description

The problem applies to transforms that use more than 1 CCS cluster or 1 local and 1 CCS as source. A typical source could look like this (the important part: `remotes*`):

```
        "index" : [
          "remotes*:filebeat*"
        ],

```

If 2 indices share the same name the transform might fail with an error similar to this:

```
 Failed to retrieve checkpoint due to: Duplicate key logs-2022-11-14 (attempted merging values [... and ...]
```

Similar to the above the `_stats` call is broken for such a transform, it can fail with an error message starting with:

```
Failure during checkpoint retrieval
```

This can happen even if the transform is in state `STOPPED` or `FAILED`.

### Mitigation

Choose _one_ of the following mitigations:

 - split your transforms to use max 1 CCS/local indices

_or_

 - avoid upgrading to 8.2, until the issue got resolved (this is a regression of #80984)

_or_

 - avoid duplicate names for your indices even on remote cluster, e.g. name the index: `remote1-filebeat...`, `remote2-filebeat...`


### Solution

This is a regression of #80984 which introduced a new way of check-pointing. The remote needs to be prefixed to the index name.
x-pack/plugin/transform/src/test/java/org/elasticsearch/xpack/transform/checkpoint/DefaultCheckpointProviderTests.java
private static Logger checkpointProviderLogger = LogManager.getLogger(DefaultCheckpointProvider.class);
    private Clock clock;
    private Client client;
    private IndexBasedTransformConfigManager transformConfigManager;
    private MockTransformAuditor transformAuditor;
    @Before
    public void setUpMocks() {
        clock = Clock.fixed(Instant.now(), ZoneId.systemDefault());
        ThreadPool threadPool = mock(ThreadPool.class);
        when(threadPool.getThreadContext()).thenReturn(new ThreadContext(Settings.EMPTY));
        client = mock(Client.class);
        when(client.threadPool()).thenReturn(threadPool);
        transformConfigManager = mock(IndexBasedTransformConfigManager.class);
        transformAuditor = MockTransformAuditor.createMockAuditor();
    }
    public void testReportSourceIndexChangesRunsEmpty() throws Exception {
        String transformId = getTestName();
        TransformConfig transformConfig = TransformConfigTests.randomTransformConfig(transformId);