The most serious is that it measures twice as AC current. In measurements with 1-100uF capacitor failure.
The precision resistor network is not required when doing a current measurement. The meter measures the voltage drop across the internal precision current shunt to get an ampere reading.
Questions for you so I can make suggestions.
1) Does DCV work in all ranges? 5V, 50 and 500V?
2) Does ohms work in all ranges?
3) Does ACV work when measuring mains?
4) Does DC current work?
5) Can you give us an example of double the AC current measurement?
6) Does uA AC work?
7) Does mA AC work?
8] Does measuring a 1000uF capacitor work?
9) Can we get clear focused pictures of your pcb? Both sides.