diff --git a/Tusker/Screens/Conversation/ConversationCollectionViewController.swift b/Tusker/Screens/Conversation/ConversationCollectionViewController.swift
index f0274978..3431f273 100644
--- a/Tusker/Screens/Conversation/ConversationCollectionViewController.swift
+++ b/Tusker/Screens/Conversation/ConversationCollectionViewController.swift
@@ -336,8 +336,9 @@ extension ConversationCollectionViewController: UICollectionViewDelegate {
                 selected(status: id, state: state.copy())
             }
         case .expandThread(childThreads: let childThreads, inline: _):
-            if case .status(id: _, node: let node, state: let state, _, _) = dataSource.itemIdentifier(for: IndexPath(row: indexPath.row - 1, section: indexPath.section)) {
-                let tree = ConversationTree(ancestors: buildNewAncestors(above: indexPath), mainStatus: node)
+            let indexPathBeforeExpandThread = IndexPath(row: indexPath.row - 1, section: indexPath.section)
+            if case .status(id: _, node: let node, state: let state, _, _) = dataSource.itemIdentifier(for: indexPathBeforeExpandThread) {
+                let tree = ConversationTree(ancestors: buildNewAncestors(above: indexPathBeforeExpandThread), mainStatus: node)
                 let conv = ConversationViewController(preloadedTree: tree, state: state.copy(), mastodonController: mastodonController)
                 conv.statusIDToScrollToOnLoad = childThreads.first!.status.id
                 conv.showStatusesAutomatically = showStatusesAutomatically