Compose中令人疑惑的地方，请大神指点

在Android Studio中学习，碰到了令人疑惑的地方，请路过大神指点！ （1）第一段代码

@Composable
fun Test() {
    Log.d("调试","开始执行..")
    var count by remember{ mutableStateOf(0) }
    Column {
        val list = mutableListOf("A","B","C","D")
        Log.d("调试","a,count="+count.toString())
        for (num in list){
            Text(text ="当前字母：$num")
            Log.d("调试","b,count="+count.toString())
            count++
            Log.d("调试","c,count="+count.toString())
            Log.d("调试","d,count="+count.toString())
        }
        Log.d("调试","e,count="+count.toString())
        Text(text = "一共 $count 个字母")
        count++
        Log.d("调试","f,count="+count.toString())
    }
}

运行界面以及调试结果如下：

从运行结果看，代码块Test()不会自动重组。

（2）第二段代码

fun Test1() {
    Log.d("调试","开始执行..")
    var count by remember{ mutableStateOf(0) }
    //代码之前加一个图片
    Column(modifier = Modifier.padding(150.dp,0.dp,0.dp,0.dp)) {
        Image(painter =  painterResource(id = R.drawable.tv_fuya), contentScale= ContentScale.FillHeight, alignment = Alignment.Center , contentDescription =null,modifier = Modifier
        )
    }
    //原始代码
    Column {
        val list = mutableListOf("A","B","C","D")
        Log.d("调试","a,count="+count.toString())
        for (num in list){
            Text(text ="当前字母：$num")
            Log.d("调试","b,count="+count.toString())
            count++
            Log.d("调试","c,count="+count.toString())
            Log.d("调试","d,count="+count.toString())
        }
        Log.d("调试","e,count="+count.toString())
        Text(text = "一共 $count 个字母")
        count++
        Log.d("调试","f,count="+count.toString())
    }
}

运行界面以及调试结果如下：

在第一代码之前加一个图片，代码块Test1()就自动重组了！

（3）第三段代码

@Composable
fun Test2() {
    Log.d("调试","开始执行..")
    var count by remember{ mutableStateOf(0) }
    //原始代码
    Column {
        val list = mutableListOf("A","B","C","D")
        Log.d("调试","a,count="+count.toString())
        for (num in list){
            Text(text ="当前字母：$num")
            Log.d("调试","b,count="+count.toString())
            count++
            Log.d("调试","c,count="+count.toString())
            Log.d("调试","d,count="+count.toString())
        }
        Log.d("调试","e,count="+count.toString())
        Text(text = "一共 $count 个字母")
        count++
        Log.d("调试","f,count="+count.toString())
    }
    //代码之后加一个图片
    Column(modifier = Modifier.padding(150.dp,0.dp,0.dp,0.dp)) {
        Image(painter =  painterResource(id = R.drawable.tv_fuya), contentScale= ContentScale.FillHeight, alignment = Alignment.Center , contentDescription =null,modifier = Modifier
        )
    }
}

运行界面以及调试结果如下：

在第一代码之后加一个图片，代码块Test2()就不会自动重组了？这是什么原因呢？