Hi,
I just had a look at this issue, it appears there is a bug on cbrestore that causes errors when there where mid flight transactions in the backup. I have opened a ticket for it MB-42967
This will be fixed in the next mayor release. Note that cbresotre and cbbackup will be deprecated in favour of cbbackupmgr. cbbackupmgr is not affected by this bug and will be available for the 1st time in Community Edition in 7.0.