I had a similar issue. In the end, they were unable to hardwire mine due to distance, so I upgraded the home WiFi. It has been great ever since.UPDATE from a friend at Tesla:
"found the issue, your neurio has terrible connection to the gateway and it’s causing the gateway to get confused by what is actually going from and to the site so to prevent an energy overload, it just lets the grid take over. it’s a safety thing."
They're going to schedule a site visit for me to hardwire
Personally, I think that the neurio's have a pathetic range on their WiFi, even with the antenna outside a metal enclosure. My portable devices were showing 2-3bars at the neurio, and it couldn't hold a connection for a few measly bits of information. (A kb a minute?)
All the best,
BG