diff --git a/kong/clustering/services/sync/rpc.lua b/kong/clustering/services/sync/rpc.lua
index 3d3ec5360890..0bf5f3b07cd7 100644
--- a/kong/clustering/services/sync/rpc.lua
+++ b/kong/clustering/services/sync/rpc.lua
@@ -87,7 +87,7 @@ function _M:init_cp(manager)
     end
 
     local latest_version, err = self.strategy:get_latest_version()
-    if not latest_version then
+    if latest_version == nil or latest_version == ngx_null then
       return nil, err
     end
 
diff --git a/kong/clustering/services/sync/strategies/postgres.lua b/kong/clustering/services/sync/strategies/postgres.lua
index 39c550b8ffb0..210c2bc6c18e 100644
--- a/kong/clustering/services/sync/strategies/postgres.lua
+++ b/kong/clustering/services/sync/strategies/postgres.lua
@@ -81,7 +81,7 @@ function _M:insert_delta(deltas)
     buf:putf("(new_version, %s, %s, %s, %s)",
              self.connector:escape_literal(d.type),
              self.connector:escape_literal(d.id),
-             self.connector:escape_literal(d.ws_id),
+             self.connector:escape_literal(d.ws_id or kong.default_workspace),
              self.connector:escape_literal(cjson_encode(d.row)))
   end