proguard leads to exception

[RuanJH]

java.lang.reflect.InvocationTargetException
at java.lang.reflect.Constructor.newInstance0(Native Method)
at java.lang.reflect.Constructor.newInstance(Constructor.java:343)
at kotlin.reflect.jvm.internal.calls.CallerImpl$Constructor.call(CallerImpl.kt:41)
at kotlin.reflect.jvm.internal.KCallableImpl.call(KCallableImpl.kt:108)
at kotlin.reflect.jvm.internal.KCallableImpl.callDefaultMethod$kotlin_reflection(KCallableImpl.kt:159)
at kotlin.reflect.jvm.internal.KCallableImpl.callBy(KCallableImpl.kt:112)
at com.dsc.form_builder.FormState.getData(FormState.kt:37)

I have kept the entire form-builder unobfuscated and also kept the corresponding objects, but it still causes reflection exceptions.