As requested I took a look at my VM-3P75CT Energy Monitor after the upgrade.
Good news: Split phase now “sticks” and phase 3 is simply not reported. Much cleaner, thank you!
Bad news: L1 is now reporting negative wattages while L2 is reporting positive. The system is setup to NOT export power to the grid. As a sanity check: I threw my main AC breaker and confirmed zero volts on the grid side, so it appears to be a reporting issue.
Data on the Cerbo screen reflects what the Energy Monitor is saying:
Future request: Add a master setting on the Cerbo that can easily and clearly be displayed to electric company technicians. Perhaps something like “Allow AC Grid feed” (yes/no) someplace high up, like the System Setup screen on the Cerbo. Obviously that should override any other settings in attached inverters that would allow for a feed.