Troubleshooting question

[simoncn]

Thanks for this. As you have suspected, it seems to be an issue with the NAS as this is the only component that is involved in all the problem scenarios.

How is the NAS network connection configured? Are you using link aggregation for the two Ethernet ports on the NAS or are there any other custom settings? It would be a good idea to post to the Synology forums about this problem if you haven't done so already.