alaba 678

according to the photos you posted. 
the one where it shows 28v, and 737w Output. 
that is not your batteries output. but the inverter output. 
PV supplies the DC to DC converter, DC does to the batteries, and from there it supplies the DC to AC inverter. 
the one picture shows 1A, this could very well be how much is drawn from the battery, and this is not constant. 
 
i have similar display, and hooked up to various monitoring items. and been staring at them for weeks now to see the trend and understand how they function and react. 
if and when the PV panels produce for instance 800w, and your load is 800w. (for arguments sake, knowing it wont be an exact match as there is losses)
and your load drops to 300w. then the excess amps runs into the battery until the MPPT can respond and reduce its output (raise the volts and reduce the amps). that will let your battery volts run up slightly, and since you are on the higher end of the voltage curve of lithium, it ramps the volts rather quickly. 
- my inverter then draws current from the battery to reduce the voltage back to the set float/charge setting it is currently in and settles. hence why you will get amperage draws from the battery, even though its fully charged, and the PV is providing more than enough. this is only until the voltage settles again. 
 
so what i am saying, you are misunderstanding the display.  

Ok, but I'm saying that the battery current will be low (a few amps at most), and there isn't hardware to measure the battery current directly. So the firmware has to estimate that current, based on measurements it has available, and guessing efficiencies and the like. The result is that the firmware does not and can not know the exact battery current, and at these low currents, it doesn't even know which direction battery current is flowing.
So I'm pretty sure that you won't be able to fix this minor problem with a firmware update. The latest firmware I have for this model is 41.17 from late 2020.

Welcome on the forum. 
Can you perhaps share pictures of the load and battery current as well as the PV value as this would help.