Once you get Sense solar, you will see two things in all the displays.
Total Consumption of your house (net usage plus Solar Production)
Solar Production - power coming from your solar back-feed.
With data export you can calculate hourly net power. The one thing you won’t be able to pull out is exactly how much accumulated real-time energy you took in from the grid and exactly how much power you have exported to the grid. You’ll only get the hourly nets.
I ran across this thread having experienced the same problem over the past 3 weeks. It’s becoming more frequent, now occurring every 2-3 days. Sometimes it will resolve on it’s own within 6 to 24 hours, or I can fix it by cycling the sense monitor power. When in the problem state solar output is incorrect, and one of the mains reads negative power.