We did yesterday an installation (Fronius Symo at AC-in) with ET340 meter, 1x Multiplus II GX, 2x Multiplus II 3000VA (last version with M8 battery terminals), and 15kWh BYD. Updated the firmware of all the inverters to 2629. GX version is 2.3. Phase numbers and direction its fine, works fine "default mode", with the three inverters charging the batteries from the grid, and inverting, but with ESS, it syncronizes with the grid for about 1second, and goes back to ESS invert mode. There's no error at all at the Venus, no #11 error, nothing, no explanation why is behaving like that. Grid is "other", and mains voltage is perfect, about 227v 50.2Hz.