diff --git a/app/src/main/kotlin/io/flamenet/messenger/app/ChatScreens.kt b/app/src/main/kotlin/io/flamenet/messenger/app/ChatScreens.kt
index d19fe95..220f4a3 100644
--- a/app/src/main/kotlin/io/flamenet/messenger/app/ChatScreens.kt
+++ b/app/src/main/kotlin/io/flamenet/messenger/app/ChatScreens.kt
@@ -1715,8 +1715,17 @@ fun ColumnScope.ChatScreen(
     val listState = rememberLazyListState()
 
     // Open AT the newest message, a jump, not a tour of the history.
+    //
+    // `requestScrollToItem`, not `scrollToItem`, here and for the keyboard
+    // below. `scrollToItem` forces a layout on the spot, and this screen is
+    // composed inside the Scaffold's MEASURE pass, so an effect that runs
+    // straight away asks for a layout in the middle of one:
+    // "performMeasureAndLayout called during measure layout", thrown from the
+    // keyboard effect in the on-device suite (ChatFlowTest, 2026-09-18 to
+    // 09-28). The request is applied by the next layout instead, which comes
+    // at once because the keyboard is what is changing the layout.
     LaunchedEffect(Unit) {
-        if (chat.lines.isNotEmpty()) listState.scrollToItem(chat.lines.lastIndex)
+        if (chat.lines.isNotEmpty()) listState.requestScrollToItem(chat.lines.lastIndex)
     }
     // Follow the conversation as it grows.
     LaunchedEffect(chat.lines.size) {
@@ -1737,7 +1746,7 @@ fun ColumnScope.ChatScreen(
     // of that lands short by however much the viewport shrank afterwards.
     val imeBottom = WindowInsets.ime.getBottom(LocalDensity.current)
     LaunchedEffect(imeBottom) {
-        if (chat.lines.isNotEmpty()) listState.scrollToItem(chat.lines.lastIndex)
+        if (chat.lines.isNotEmpty()) listState.requestScrollToItem(chat.lines.lastIndex)
     }
 
     // One bar, not three stacked rows, and it wears the channel's own colour.
diff --git a/app/src/test/kotlin/io/flamenet/messenger/app/TheKeyboardDoesNotHideTheMessagesTest.kt b/app/src/test/kotlin/io/flamenet/messenger/app/TheKeyboardDoesNotHideTheMessagesTest.kt
index 0034f7d..54ac025 100644
--- a/app/src/test/kotlin/io/flamenet/messenger/app/TheKeyboardDoesNotHideTheMessagesTest.kt
+++ b/app/src/test/kotlin/io/flamenet/messenger/app/TheKeyboardDoesNotHideTheMessagesTest.kt
@@ -58,10 +58,19 @@ class TheKeyboardDoesNotHideTheMessagesTest {
         // The inset arrives as a series of values while the keyboard slides.
         // One animated jump fired at the start of that lands short by however
         // much the viewport shrank afterwards.
+        //
+        // Instant means `requestScrollToItem`, applied by the next layout, and
+        // NOT `scrollToItem`, which forces a layout on the spot: this screen is
+        // composed inside the Scaffold's measure pass, and on-device that threw
+        // "performMeasureAndLayout called during measure layout".
         val block = screens.substringAfter("LaunchedEffect(imeBottom) {").substringBefore("}")
         assertTrue(
-            block.contains("listState.scrollToItem("),
-            "the keyboard follow should scroll instantly: $block",
+            block.contains("listState.requestScrollToItem("),
+            "the keyboard follow should scroll instantly, by request: $block",
+        )
+        assertTrue(
+            !block.contains("listState.scrollToItem("),
+            "scrollToItem forces a layout and throws when it runs inside one: $block",
         )
         assertTrue(
             !block.contains("animateScrollToItem"),