**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/main/java/org/elasticsearch/xpack/transform/checkpoint/DefaultCheckpointProvider.java
ActionListener<TransformCheckpoint> nextCheckpointListener = ActionListener.wrap(nextCheckpointObj -> {
            checkpointingInfoBuilder.setNextCheckpoint(nextCheckpointObj);
            getIndexCheckpoints(checkpointsByIndexListener);
        }, e -> {
            logger.debug(
                () -> format("[%s] failed to retrieve next checkpoint [%s]", transformConfig.getId(), lastCheckpointNumber + 1),
                e
            );
            listener.onFailure(new CheckpointException("Failure during next checkpoint info retrieval", e));
        });
        
        ActionListener<TransformCheckpoint> lastCheckpointListener = ActionListener.wrap(lastCheckpointObj -> {
            checkpointingInfoBuilder.setChangesLastDetectedAt(Instant.ofEpochMilli(lastCheckpointObj.getTimestamp()));
            checkpointingInfoBuilder.setLastCheckpoint(lastCheckpointObj);
            transformConfigManager.getTransformCheckpoint(transformConfig.getId(), lastCheckpointNumber + 1, nextCheckpointListener);
        }, e -> {
            logger.debug(() -> format("[%s] failed to retrieve last checkpoint [%s]", transformConfig.getId(), lastCheckpointNumber), e);
            listener.onFailure(new CheckpointException("Failure during last checkpoint info retrieval", e));
        });
        if (lastCheckpointNumber != 0) {
            transformConfigManager.getTransformCheckpoint(transformConfig.getId(), lastCheckpointNumber, lastCheckpointListener);
        } else {
            getIndexCheckpoints(checkpointsByIndexListener);
        }
    }
    /**
     * Inspect source changes and report differences
     *
     * @param lastSourceIndexes the set of indexes seen in the previous checkpoint