diff --git a/app/src/main/java/eu/faircode/email/AdapterMessage.java b/app/src/main/java/eu/faircode/email/AdapterMessage.java
index 18c1a46662..7e19bf9c15 100644
--- a/app/src/main/java/eu/faircode/email/AdapterMessage.java
+++ b/app/src/main/java/eu/faircode/email/AdapterMessage.java
@@ -3561,7 +3561,9 @@ public class AdapterMessage extends RecyclerView.Adapter<AdapterMessage.ViewHold
 
                 @Override
                 protected void onException(Bundle args, Throwable ex) {
-                    Log.unexpectedError(parentFragment.getParentFragmentManager(), ex);
+                    // https://github.com/mangstadt/biweekly/issues/121
+                    if (!(ex instanceof AssertionError))
+                        Log.unexpectedError(parentFragment.getParentFragmentManager(), ex);
                 }
             }.setLog(false).execute(context, owner, args, "message:calendar");
         }
@@ -3805,7 +3807,8 @@ public class AdapterMessage extends RecyclerView.Adapter<AdapterMessage.ViewHold
 
                 @Override
                 protected void onException(Bundle args, Throwable ex) {
-                    Log.unexpectedError(parentFragment.getParentFragmentManager(), ex);
+                    if (!(ex instanceof AssertionError))
+                        Log.unexpectedError(parentFragment.getParentFragmentManager(), ex);
                 }
             }.execute(context, owner, args, "message:participation");
         }