Update warehouse-syncs.md

Author: pmbasco

src/connections/storage/warehouses/warehouse-syncs.md

@@ -69,6 +69,9 @@ When you disable a source, collection or property, Segment no longer syncs data
 > warning ""
 > For each warehouse only the first 5,000 collections per source and 5,000 properties per collection are visible in the Selective Sync user interface. [Learn more about the limits](#selective-sync-user-interface-limits).
 
+> warning ""
+> All tables use `receieved_at` for the sort key, disabling this column will cause your syncs to fail.
+ 
 ### When to use Selective Sync
 
 By default, all sources and their collections and properties are sent, and no data is prevented from reaching warehouses.