There are a lot of overlapping numbers. I'm not a PHEV owner, but your 50% charge level might refer to your total battery charge (it is actually less as there is a "buffer"). The 6 mile estimate would just be the remaining initial plug in charge. Those are two different concepts. Takes a while to wrap your head around it. The battery contains both your plug in charge and the HEV minimum in one pot. Those numbers are just different ways to visualize the same exact state of charge.
I am a PHEV owner, and I concur.
The algorithms Kia uses to calculate battery % are unknown by us consumers - all we know is that a full charge = 26 miles (give or take), and an "empty" (0 EV miles remaining) charge really equals a 25% charge remaining, which is the amount that the car allocates to the HEV drive. The battery could theoretically drive the car about 32 miles on battery alone, but during the last 6 miles-worth of battery life, it switches to HEV mode. The calcs on the meter, the calcs on your app, and other calcs will not necessarily coincide, as a result. The meters would be quite accurate for an EV-only car, but for a PHEV it gets really complicated.
Based on what you're describing, it sounds like nothing is wrong. The calculations aren't jiving, but that's ok. Generally speaking, the "miles remaining" on the meter on your dashboard is accurate - when it says 13 miles (1/2 of 26) remain, it means that the EV portion of the battery is at 50%, but really the battery has about 63% usable capacity remaining (with 13% reserved for HEV mode), and further, the battery ACTUALLY probably really has 72% remaining because it only allows for about an 80% charge to preserve battery life.
For what it's worth, the 26 mile range is a real
number, based on all those factors. I have almost exactly measured 26 miles per charge on my PHEV. Some trips I get 24, some trips I get 30, but on average I get exactly 26 miles of EV from each charge.