Multiple triggers on S3 bucket?

Scratching my head on this one, maybe it's not possible but I can't see why not if so.

I have an S3 bucket with two event notifications configured.

1. The first is for Put of objects with prefix 'CB' and suffix '.eml'. The target is a lambda function called 'Reporter'.
2. The second is for Put and Delete of objects with prefix 'CB' and suffix '.zip'. The target is a lambda function called 'Launcher'.

The second works fine: the Launcher function is called with the correct event when a matching object is added or removed from the bucket. However the first one never fires, as there are no log streams generated in the log group for the lambda function.

Is there any obvious reason? e.g. only one trigger is allowed per bucket? I don't really know how to troubleshoot this further, as there are no logs that I'm aware of that would contain a "trigger failed" entry.

The configuration looks fine:

$ aws s3api get-bucket-notification-configuration --bucket <bucket_name>
{
    "LambdaFunctionConfigurations": [
        {
            "Id": "Launch/Terminate trigger",
            "LambdaFunctionArn": "arn:aws:lambda:eu-west-1:<acc_id>:function:Launcher",
            "Events": [
                "s3:ObjectCreated:*",
                "s3:ObjectRemoved:*"
            ],
            "Filter": {
                "Key": {
                    "FilterRules": [
                        {
                            "Name": "Prefix",
                            "Value": "CB"
                        },
                        {
                            "Name": "Suffix",
                            "Value": ".zip"
                        }
                    ]
                }
            }
        },
        {
            "Id": "Email trigger",
            "LambdaFunctionArn": "arn:aws:lambda:eu-west-1:<acc_id>:function:Reporter",
            "Events": [
                "s3:ObjectCreated:*"
            ],
            "Filter": {
                "Key": {
                    "FilterRules": [
                        {
                            "Name": "Prefix",
                            "Value": "CB"
                        },
                        {
                            "Name": "Suffix",
                            "Value": ".eml"
                        }
                    ]
                }
            }
        }
    ]
}

The S3 permissions on each of the target lambda functions are also OK:

Reporter lambda permissions:

Statement ID trigger-Reporter
Principal s3.amazonaws.com
Effect Allow
Action lambda:InvokeFunction
Conditions
{
  "ArnLike": {
        "AWS:SourceArn": "arn:aws:s3:::<bucket_name>"
  }
}

Launcher lambda permissions:

Statement ID trigger-Launcher
Principal s3.amazonaws.com
Effect Allow
Action lambda:InvokeFunction
Conditions
{
  "ArnLike": {
        "AWS:SourceArn": "arn:aws:s3:::<bucket_name>"
  }
}

Thanks,

David