In many cases, the bar can stop at the moment when it collapses. Then the title is shown twice and you have to swipe up or down again to get a proper AppBar again.

Another problem is that if you scroll up and the bar is about to expand, but you don't scroll far enough and it collapses again, you get kicked all the way down in the screen (no matter how long it is).

Jetpack Compose version: 1.2.0 (for m3: 1.0.0-alpha15) Jetpack Compose component used: M3 Scaffold with MediumTopAppBar Android Studio Build: Android Studio Electric Eel | 2022.1.1 Canary 8 Kotlin version: 1.7.0

Code Sample to Reproduce:

@OptIn(ExperimentalMaterial3Api::class)
@Composable
fun MainScreen() {
    val decayAnimationSpec = rememberSplineBasedDecay<Float>()
    val scrollBehavior = TopAppBarDefaults.exitUntilCollapsedScrollBehavior(
        decayAnimationSpec,
        rememberTopAppBarState()
    )

    Scaffold(
        modifier = Modifier.nestedScroll(scrollBehavior.nestedScrollConnection),
        topBar = {
            AppBar(
                scrollBehavior = scrollBehavior
            )
        }
    ) { padding ->
        Surface(
            modifier = Modifier.padding(paddingValues = padding),
            color = MaterialTheme.colorScheme.background
        ) {
            ScreenWithColumn()
        }
    }
}

@OptIn(ExperimentalMaterial3Api::class)
@Composable
fun AppBar(
    scrollBehavior: TopAppBarScrollBehavior
) {
    MediumTopAppBar(
        title = {
            Text(text = "This is a title")
        },
        colors = TopAppBarDefaults.mediumTopAppBarColors(
            containerColor = MaterialTheme.colorScheme.background,
            scrolledContainerColor = MaterialTheme.colorScheme.surface
        ),
        scrollBehavior = scrollBehavior
    )
}

Issue 240762124

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