After leaving the fragment to the previous fragment and changing the orientation, the editText must not be null?

Question

Java

java.lang.IllegalStateException: fah_edtFname must not be null
From Fragment A I press the button and Fragment B opens, in it I save the values ​​​​of all EditText' s, when I flip the screen, everything typed is saved, but as soon as I return to Fragment A and change orientation screen, the error java.lang.IllegalStateException: fah_edtFname must not be null, (fah_edtFname is EditText), that is, if I go to Fragment B, then press the back arrow and it returns me to the previous Fragment A, and press change orientation, then being in fragment A, I get an error that in the closed fragment B, my edit texts are null ..

override fun onSaveInstanceState(outState: Bundle) {
        super.onSaveInstanceState(outState)
        val human = saveChangedText()
        outState.putParcelable("savedText",human)
    }
    fun saveChangedText():Human?{
            val firstName = fah_edtFname.text.toString()
            val lastName=fah_edtLastName.text.toString()
            val age =fah_edtAge.text.toString()
            val job = fah_edtJob.text.toString()
            return Human(first_name = firstName,last_name = lastName,age = age,job = job)
    }

I solved the error, I put a check - if the edit texts are not null, then save their text, but I don’t understand why, if the fragment is already closed, then I still try to work out onSaveInstanceState in it?