Odd how it is only on those 2 days, the 1st and 4th of October.
Do you have an electric HWS ?
If so, it's likely this is on CL (controlled load) still, and that is metered separately, solar and battery will not have an effect on that.
It is odd that you'd expect that to come on every day though, not just the 2 days out of 5 shown.
When you click on the days in that graph, does it break down the time of day for usage, and if so is that in solar soak and / or old off peak times ?
If it could be the HWS, then you will see controlled load on your plan info.
I did a simple mod to fix this and happy to share if you let me know about the HW possibility.