I've just recieved an email saying that the latest version has fixed this although i've not tried it yet.

While we will be investigating your current issue you can update your backup agent to the latest version. We released it (v. 4.0.2.402)

The support didn't really help much regarding the error

They advised to delete the backup job and set it back up on the new beta method included in version 4

Seems to be working so far but has its own problems

Yes it is local storage In cloudberry.

The plan which goes to backblase works fine