Presently, the backup-manager ebuild doesn't even list find-utils as a depend. I recently upgraded from backup-manager-0.7.4 to 0.7.5 and noticed that it no longer purged old backups. This was due to a "find" syntax change in the scripts. Please add findutils >=4.3.0 to the list of backup-manager depends Reproducible: Always
Sigh; upgrade your system properly using emerge -uD world. Current stable is 4.3.2-r1 everywhere.
Can you please elaborate on what has changed regarding the find usage? The dependency has been added to 0.7.5, thanks for your report.