IssueTracker

Thanks for supplying us with the reproducible sample, I have verified that it is indeed a bug that needs fixing.

We are working on a fix in RecyclerView and in ViewPager2. In the mean time, you can try the following workaround:

Override onConfigurationChanged in your Activity, and record the currentItem of ViewPager2, and add a OnLayoutChangeListener to ViewPager2 that consumes this variable by making sure RecyclerView is scrolled to the right location. Here is an outline of a workaround:

viewPager.addOnLayoutChangeListener { v, left, top, right, bottom, oldLeft, oldTop, oldRight, oldBottom ->
    val horizontal = viewPager.orientation == ViewPager2.ORIENTATION_HORIZONTAL
    val rtl = ViewCompat.getLayoutDirection(viewPager) == ViewCompat.LAYOUT_DIRECTION_RTL

    if (currentItemBeforeConfigChange != RecyclerView.NO_POSITION) {
        val currentItem = currentItemBeforeConfigChange
        currentItemBeforeConfigChange = RecyclerView.NO_POSITION

        val rv = viewPager.getChildAt(0) as RecyclerView
        val child = rv.getChildAt(0)
        val childPosition = rv.getChildLayoutPosition(child)
        val pxPerItem = if (horizontal) {
            if (rtl) -child.width else child.width
        } else {
            child.height
        }
        val expectedChildLocation = pxPerItem * (childPosition - currentItem)
        val actualChildLocation = if (horizontal) child.left else child.top
        val scrollDistance = actualChildLocation - expectedChildLocation
        rv.scrollBy(
            if (horizontal) scrollDistance else 0,
            if (!horizontal) scrollDistance else 0
        )
    }
}

Please make sure to tweak this to your application's needs

The fix (https://android-review.googlesource.com/1221510) will be released in the next release of viewpager2

Note: while no new version of viewpager2 is released, one can unblock oneself by adding an explicit dependency to the latest alpha version of recyclerview (androidx.recyclerview:recyclerview:1.2.0-alpha03 at the time of writing).