yeah exactly, had to go into "installer mode" and configure the CT that's on a secondary powerwall, so it wouldn't count that value as part of the generation (forget the exact cryptically named option). Otherwise it considered energy pushed towards that powerwall as "additional energy in the system", and since the grid ct didn't show it was coming from there, it was assuming that the generation must be coming from solar. Or so it seemed.
from the looks of it, his CTs are mis-reporting/double counting. A very common problem with tesla installs. My solar roof had the same issue initially, and electricians really thought it was generating more then the rating of the inverters, until I fixed it (software controlled). With 3 inverters he can't have more than ~23kw AC (assuming each is 7.8kw, which is the largest inverters tesla had at the time). My solar roof is a bit smaller (~21kw), in a similar region, but the daily peaks are slightly less than half of what he was showing.