To be clearer, I drilled a hole and installed a rubber grommet between the service and user sides of the panel, powered the sense down, moved the CT’s from the 200A leg to the 400A supply side, and powered back on.
The reported usage was excessively high, seemed something was wrong, I cycled breakers one-by-one (in both 200A panels), and observed no drop in usage. When I cycled the solar feed breaker, the sense stopped reporting, as if it reset. I power cycled the sense, it came back online, and reported very low usage.
I decided to do a data reset, did the solar off-on dance, and solar started reporting, but usage stayed at 0. When I look at the device details I can see usage is -700W, assuming solar is feeding the grid, but the dashboard reports 0W usage and 3KW solar generation.
Something is funky, I contacted support and asked for help.