Fallback once

app/src/main/java/eu/faircode/email/ViewModelMessages.java

@@ -255,6 +255,7 @@ public class ViewModelMessages extends ViewModel {
 
         Log.d("Observe previous/next id=" + id);
         model.list.observe(owner, new Observer<PagedList<TupleMessageEx>>() {
+            private boolean fallback = false;
 
             @Override
             public void onChanged(PagedList<TupleMessageEx> messages) {
@@ -283,6 +284,11 @@ public class ViewModelMessages extends ViewModel {
 
                 Log.w("Observe previous/next gone id=" + id);
 
+                if (fallback)
+                    return;
+
+                fallback = true;
+
                 Bundle args = new Bundle();
                 args.putLong("id", id);