Pruning of backup files skipped apparently without reason

HI, Im having unexpect issues with my backups, all backup task ends with: [2020-12-29 02:05:58 +0100] info [backup] Final state is Backup::PartialFailure (0) [2020-12-29 02:05:58 +0100] info [backup] Sent Backup::PartialFailure notification. I"ve tried to check the reason but if i grep for "fail" or "error" just this appears: /usr/bin/gtar returned a non-fatal error code, 1 (Some files differ). [2020-12-29 02:05:58 +0100] warn [backup] Pruning of backup files skipped due to errors. at /usr/local/cpanel/bin/backup line 395. I dont know the reason and i am not able to resolve the issue. This errors performs that the backup"s size increase a lot because of not rotation. Thanks