diff --git a/golibdave/golibdave.go b/golibdave/golibdave.go
index 857625d..4de12bb 100644
--- a/golibdave/golibdave.go
+++ b/golibdave/golibdave.go
@@ -192,6 +192,10 @@ func (s *session) prepareEpoch(epoch int, protocolVersion uint16) {
 		return
 	}
 
+	s.logger.Warn("prepareEpoch: resetting MLS session via Init",
+		slog.Int("epoch", epoch),
+		slog.Int("protocol_version", int(protocolVersion)),
+	)
 	s.session.Init(protocolVersion, uint64(s.channelID), string(s.selfUserID))
 }
 
@@ -228,17 +232,33 @@ func (s *session) setupKeyRatchetForUser(userID godave.UserID, protocolVersion u
 	disabled := protocolVersion == disabledProtocolVersion
 
 	if userID == s.selfUserID {
+		kr := s.session.GetKeyRatchet(string(userID))
+		if !disabled && kr == nil {
+			s.logger.Warn("nil key ratchet for self after GetKeyRatchet",
+				slog.String("user_id", string(userID)),
+				slog.Int("protocol_version", int(protocolVersion)),
+			)
+			return
+		}
 		s.encryptor.SetPassthroughMode(disabled)
 		if !disabled {
-			s.encryptor.SetKeyRatchet(s.session.GetKeyRatchet(string(userID)))
+			s.encryptor.SetKeyRatchet(kr)
 		}
 		return
 	}
 
 	decryptor := s.decryptors[userID]
+	kr := s.session.GetKeyRatchet(string(userID))
+	if !disabled && kr == nil {
+		s.logger.Warn("nil key ratchet for user after GetKeyRatchet",
+			slog.String("user_id", string(userID)),
+			slog.Int("protocol_version", int(protocolVersion)),
+		)
+		return
+	}
 	decryptor.TransitionToPassthroughMode(disabled)
 	if !disabled {
-		decryptor.TransitionToKeyRatchet(s.session.GetKeyRatchet(string(userID)))
+		decryptor.TransitionToKeyRatchet(kr)
 	}
 }
 
diff --git a/libdave/key_ratchet.go b/libdave/key_ratchet.go
index c8d3b5f..2cb5e42 100644
--- a/libdave/key_ratchet.go
+++ b/libdave/key_ratchet.go
@@ -11,6 +11,10 @@ type KeyRatchet struct {
 }
 
 func newKeyRatchet(handle keyRatchetHandle) *KeyRatchet {
+	if handle == nil {
+		return nil
+	}
+
 	keyRatchet := &KeyRatchet{handle: handle}
 
 	runtime.SetFinalizer(keyRatchet, func(k *KeyRatchet) {