Button的背景色基于ButtonDefaults.buttonColors()中定义的颜色。
解决方法是为disabledBackgroundColor和backgroundColor定义相同的颜色。
比如：

var isButtonEnabled by remember { mutableStateOf(true) }
val animateStateButtonColor = animateColorAsState(
    targetValue = if (isButtonEnabled) Color.Blue else Teal200,
    animationSpec = tween(2000, 0, LinearEasing)
) 

Button(
    colors = ButtonDefaults.buttonColors(
        backgroundColor = animateStateButtonColor.value,
        disabledBackgroundColor = animateStateButtonColor.value,
    ),
    enabled = isButtonEnabled,
    onClick = { /* ... */ }
) {
    Text(text = "Button")
}