niofar

If you ever figure out why, I'd love to know.

I can confirm that with the "selling first" function the anomalous consumption disappears!!!

I had a similar situation, although my setup is a little different. My 5kW Deye was operating in "Zero export to CT" mode with Solar Sell. I have loads also on my non-essential side, but the inverter's power to the non-essential always seemed well higher than the loads knew I was using.
In my case I am also registered for exporting to the municipal grid, so I activated "Selling First" and the load reading immediately dropped to my actual usage while the selling to the grid spiked up by the surplus I was generating. As if the surplus was being used internally even though the battery was full and it should have started selling.
If you can legally export, please check if it makes a difference for you too.
Why it does this? I've had a theory that the solar/battery in the CT mode was also being used to supply reactive power, or otherwise keep capacitors charged to help smooth the supply when running from unstable solar and battery blending, if the grid is not supposed to be used a "ballast". Truth is, I don't know what I'm talking about, and I really have no idea why this happens.