Problem with deleting backups on Google Cloud Storage

I have two pro Virtualmin servers (one is CentOS 7, the other is CentOS 6.6). Both backup to the same Google cloud account. There is a full backup on Sundays and an incremental backup on other days.

Each server does the backup to its own 'bucket' and a folder('full' or 'incremental'). I am using this format for the backups (one file per domain).

server1/incremental/%Y-%m-%d-%T
server2/incremental/%Y-%m-%d-%T

In each case I have "delete old backups after 10 days". Now here's the thing:

For server1, I am getting errors such as this:

Deleting backups from incremental/%Y-%m-%d-%T in Google folder server1 older than 10 days ..
Deleting file incremental/2015-01-12-07:07:05/domain.com.tar.gz, which is 15 days old ..
.. deletion failed : HTTP/1.0 404 Not Found

However at Google, I *can* see the folder "2015-01-12-07:07:05/".

For server2, the problem is different. I can see folders such as this: "2015-01-06-01:30:04/". But my backup report says this:
"Deleting backups from incremental/%Y-%m-%d-%T in Google folder spinoza older than 10 days ..
.. no backups to delete were found". In other words, no deletions are getting done!

As well as backing up to Google, I do a local backup too at the same time with the same settings. That's working fine, and files are being deleted after 10 days!

server1: /root/localVMBak/incremental/%Y-%m-%d-%T
server2: /root/localVMBak/incremental/%Y-%m-%d-%T