This error appears right after a job configuration or when trying to start the job run.
It indicates the job misconfiguration: the Agent is added to two different jobs. In one of the jobs it's configured to sync a folder with Selective Sync either enabled or enabled, while in the other - its parenting or child directory with an opposite Selective Sync setting (either disabled or enabled respectively).
The ideal solution to this is not to synchronize nested folders. If it's indeed needed, the only solution is to keep Selective Sync setting same on both jobs (both have Selective Sync either enabled or disabled).
This error has two codes: