Interestingly it did not on the 25th and 26th so not every day. I could have sworn when I scrolled through I saw every single day, not just most days which is making me wonder if there's a data logging issue except that if I turn on the grid graph, it shows the grid taking over in exactly those 5:45 to 6:05 hole.
The system set to balanced, 35% reserve, time based. Yesterday, when it stopped, the SOC was 71%, so well above reserve.