diff --git a/synapse/handlers/room.py b/synapse/handlers/room.py
index 496f1fc39..d1cc87a01 100644
--- a/synapse/handlers/room.py
+++ b/synapse/handlers/room.py
@@ -205,12 +205,12 @@ class RoomCreationHandler(BaseHandler):
                 },
                 ratelimit=False)
 
-        content = {}
-        is_direct = config.get("is_direct", None)
-        if is_direct:
-            content["is_direct"] = is_direct
-
         for invitee in invite_list:
+            content = {}
+            is_direct = config.get("is_direct", None)
+            if is_direct:
+                content["is_direct"] = is_direct
+
             yield room_member_handler.update_membership(
                 requester,
                 UserID.from_string(invitee),
diff --git a/synapse/handlers/room_member.py b/synapse/handlers/room_member.py
index 970fec066..7e6467cd1 100644
--- a/synapse/handlers/room_member.py
+++ b/synapse/handlers/room_member.py
@@ -189,6 +189,10 @@ class RoomMemberHandler(BaseHandler):
         content_specified = bool(content)
         if content is None:
             content = {}
+        else:
+            # We do a copy here as we potentially change some keys
+            # later on.
+            content = dict(content)
 
         effective_membership_state = action
         if action in ["kick", "unban"]: