Sync not working?

Hi. I am running a daily Sync job, and it’s not working - when running on a scheduled job, or when running it manually, it’s reporting ‘no changes’ and zero files changed when in fact a directory of 32 files has been deleted from the source. If I ‘dry run’ the job the outcome report correctly identifies those changes, but running the job for real doesn’t - it leaves the destination files (in Opendrive) unchanged. Can anyone shed any light? (Note that this has occurred both before and after the temporary outage of Opendrive earlier today).
Thanks for any help anyone can offer.