Max deterioration at 98% is either a glitch, or more likely it means one of the cells has failed.
The battery will need to be repaired / replaced.
In both previous cases Kia has just replaced the entire battery, rather than try to repair just a single cell.
If you download and install the soulspy app there is a voltage heatmap.
This should show you the faulty cell fairly easily.
I have a 2011 Hyundai BlueON Electric with a single faulty cell.
When charging that cell stands out because its voltage is much higher than the others. See pic below - cell 61 is the bad cell.
When driving that cell stands out because its voltage is much lower than the others.
The codes for using Torque Pro can be found by clicking the link in the website icon under my user name on the left.