My network connection to my NAS drops, and I have to click up on the Ethernet Network and select the active ethernet connection before I can connect to my NAS. This is also the case when I need to get to my Diskstation control panel via web browser.
What's strange is that my internet connection doesn't appear to be dropping out at all. I'm able to stream videos and music without issue.
I've also replaced the card with a new ethernet card. These are Intel Gigabit CT Desktop Adapters (PCI-E). The exact same behavior happens.