Replace instead of push URL in INITIALIZE_QB to avoid double back button issues:

frontend/src/metabase/query_builder/actions.js

@@ -235,6 +235,7 @@ export const initializeQB = createThunkAction(INITIALIZE_QB, (location, params)
         // clean up the url and make sure it reflects our card state
         dispatch(updateUrl(card, {
             dirty: isCardDirty(card, originalCard),
+            replaceState: true,
             preserveParameters
         }));