This is more of a bug-report than a question, as I don't believe there is any sort of configuration setting that can fix this. But if there is, I'd be glad to know about it!
I have a Carlo Gavazzi EM530 energy meter on a split-phase service feeding 2x Quattro 15kva 230v inverters (in parallel) into an auto-transformer to re-create split-phase on the output.
Since the EM530 reports the individual phase values, Venus believe the Quattros are only across L1 and passes thru L2 wattage values even when no non-critical loads are being applied.
Take this screenshot for example:
The real Total consumption is ~7000 watts and not 10,152 watts.
As I typically have large but steady/consistent non-critical loads, it took me a while to understand why they fluctuated so much (dependent on the critical loads)