diff --git a/guix/store.scm b/guix/store.scm
index efba07bdcd..88cab1bb6a 100644
--- a/guix/store.scm
+++ b/guix/store.scm
@@ -1337,7 +1337,12 @@ (define (build-accumulator expected-store)
     (if (and (eq? (store-connection-socket store)
                   (store-connection-socket expected-store))
              (= mode (build-mode normal)))
-        (unresolved things continue)
+        (unresolved things
+                    (lambda (new-store value)
+                      ;; Borrow caches from NEW-STORE.
+                      (set-store-connection-caches!
+                       store (store-connection-caches new-store))
+                      (continue value)))
         (continue #t))))
 
 (define default-cutoff
@@ -1397,7 +1402,8 @@ (define-values (result rest)
                                       (if (unresolved? obj)
                                           ;; Pass #f because 'build-things' is now
                                           ;; unnecessary.
-                                          ((unresolved-continuation obj) #f)
+                                          ((unresolved-continuation obj)
+                                           store #f)
                                           obj))
                                     result #:cutoff cutoff)
          (map/accumulate-builds store proc rest #:cutoff cutoff)))))