Cannot see snapshots from another cluster using S3 storage

Hello,

I've got two clusters sitting in different VPCs in AWS, both are on the same version (2.3.3) and both are using the AWS plugin for discovery and snapshots.

I've created several snapshots in cluster 1, I can see these in the S3 bucket and when I query for snapshots I can see them all listed in cluster 1:

curl 'localhost:9200/_cat/snapshots/my.bucket?v='
id                                status start_epoch start_time end_epoch  end_time duration indices successful_shards failed_shards total_shards 
snapshop-all-16-07-15-1468581240 SUCCESS 1468581225  11:13:45   1468581360 11:16:00     2.2m       9                37             0           37 
snapshop-all-16-07-15-1468581511 SUCCESS 1468581495  11:18:15   1468581499 11:18:19     4.1s       9                37             0           37 
snapshop-all-16-07-15-1468584084 SUCCESS 1468584068  12:01:08   1468584072 12:01:12       4s       9                37             0           37 

I've added the same repository with the same settings to cluster 2, I've also given the machine the same IAM role and checked that it can definitely access the bucket, however when I query for snapshots on cluster 2 there are none listed:

curl 'localhost:9200/_cat/snapshots/my.bucket?v='
id status start_epoch start_time end_epoch end_time duration indices successful_shards failed_shards total_shards

Is this a bug or am I doing something wrong here? Do I need to do something to get ES in cluster 2 to recognise tese snapshots?

Anything in logs?
May be you could try this in DEBUG ?