There are a few ways this can happen. Its likely not the Ekrano but the smartshunt settings. It may be that your “charged voltage” is set too low and when a charger starts charging the shunt thinks the batteries are full. For example, if your charged voltage is set to 13.8V and your Multiplus or solar is charging at 13.9 the shunt will set to 100%.
Check out this link that has answers to a lot of the most common issues like what you are experiencing. I would start with getting an understanding of how a smartshunt’s settings decide the battery is full.