Synchronization failure from parent to its children

Since one month I am having this issue. My parent server is not syncing the changes comitted on forms or concepts from the parent server to the children OpenMRS implementations. It is working on the opposite direction (children are syncing their changes to the parent server with no problem). My OpenMRS version is 1.10 and the version of the Synchronization module is 1.3-Snapshot.

On the synchronization history on the parent server I can see all the changes comitted in it and they are waiting to be synchronized, but when I when I do synchronize from the children they get nothing from the parent side. All the system was working fine one month ago. This issue started after I cleaned the /temp directory on the parent server, so I guess It is related somehow but I don’t know in which way.

Any tip or advice would be appreciated.

Thanks @michael for your help to clarify the issue a little more. Any clues then? Maybe the sync log in the parent server could be corrupted somehow?