diff --git a/federationapi/internal/perform.go b/federationapi/internal/perform.go
index c51ecf146..b888b3654 100644
--- a/federationapi/internal/perform.go
+++ b/federationapi/internal/perform.go
@@ -554,7 +554,6 @@ func (r *FederationInternalAPI) PerformInvite(
 	if err != nil {
 		return fmt.Errorf("r.federation.SendInviteV2: failed to send invite: %w", err)
 	}
-	logrus.Infof("GOT INVITE RESPONSE %s", string(inviteRes.Event))
 
 	inviteEvent, err := inviteRes.Event.UntrustedEvent(request.RoomVersion)
 	if err != nil {
diff --git a/keyserver/internal/device_list_update.go b/keyserver/internal/device_list_update.go
index c5a5d40c7..b208f0ce5 100644
--- a/keyserver/internal/device_list_update.go
+++ b/keyserver/internal/device_list_update.go
@@ -241,14 +241,33 @@ func (u *DeviceListUpdater) update(ctx context.Context, event gomatrixserverlib.
 				StreamID: event.StreamID,
 			},
 		}
+
+		// DeviceKeysJSON will side-effect modify this, so it needs
+		// to be a copy, not sharing any pointers with the above.
+		deviceKeysCopy := *keys[0].DeviceKeys
+		deviceKeysCopy.KeyJSON = nil
+		existingKeys := []api.DeviceMessage{
+			{
+				Type:       keys[0].Type,
+				DeviceKeys: &deviceKeysCopy,
+				StreamID:   keys[0].StreamID,
+			},
+		}
+
+		// fetch what keys we had already and only emit changes
+		if err = u.db.DeviceKeysJSON(ctx, existingKeys); err != nil {
+			// non-fatal, log and continue
+			util.GetLogger(ctx).WithError(err).WithField("user_id", event.UserID).Errorf(
+				"failed to query device keys json for calculating diffs",
+			)
+		}
+
 		err = u.db.StoreRemoteDeviceKeys(ctx, keys, nil)
 		if err != nil {
 			return false, fmt.Errorf("failed to store remote device keys for %s (%s): %w", event.UserID, event.DeviceID, err)
 		}
-		// ALWAYS emit key changes when we've been poked over federation even if there's no change
-		// just in case this poke is important for something.
-		err = u.producer.ProduceKeyChanges(keys)
-		if err != nil {
+
+		if err = emitDeviceKeyChanges(u.producer, existingKeys, keys); err != nil {
 			return false, fmt.Errorf("failed to produce device key changes for %s (%s): %w", event.UserID, event.DeviceID, err)
 		}
 		return false, nil
diff --git a/roomserver/storage/shared/storage.go b/roomserver/storage/shared/storage.go
index b255cfb3f..e270e121c 100644
--- a/roomserver/storage/shared/storage.go
+++ b/roomserver/storage/shared/storage.go
@@ -13,6 +13,7 @@ import (
 	"github.com/matrix-org/dendrite/roomserver/types"
 	"github.com/matrix-org/gomatrixserverlib"
 	"github.com/matrix-org/util"
+	"github.com/sirupsen/logrus"
 	"github.com/tidwall/gjson"
 )
 
@@ -1101,7 +1102,7 @@ func (d *Database) JoinedUsersSetInRooms(ctx context.Context, roomIDs []string)
 		return nil, err
 	}
 	if len(nidToUserID) != len(userNIDToCount) {
-		return nil, fmt.Errorf("found %d users but only have state key nids for %d of them", len(userNIDToCount), len(nidToUserID))
+		logrus.Warnf("SelectJoinedUsersSetForRooms found %d users but BulkSelectEventStateKey only returned state key NIDs for %d of them", len(userNIDToCount), len(nidToUserID))
 	}
 	result := make(map[string]int, len(userNIDToCount))
 	for nid, count := range userNIDToCount {