diff --git a/core/src/magic.sld b/core/src/magic.sld
index 0bb0fec..d2ceb7c 100644
--- a/core/src/magic.sld
+++ b/core/src/magic.sld
@@ -286,7 +286,15 @@
    (define (store-path-realised path)
      (define ctx (zexp-unwrap (zexp (zexp-unquote path))))
      (define val (zexp-evaluation-value ctx))
-     (define to-build '())
+     (define to-build (list))
+     (for-each
+      (lambda (drv-and-outputs)
+       (unless (drv-is-ca (car drv-and-outputs))
+         (for-each
+          (lambda (o)
+           (set! to-build (cons (string-append (derivation-path (car drv-and-outputs)) "!" o) to-build)))
+          (cdr drv-and-outputs))))
+      (zexp-evaluation-drvs ctx))
      (if (string? val)
        (let-values (((resolved resolved-to-build) (resolve-upstream-output-placeholders val (zexp-evaluation-drvs ctx))))
          (set! val resolved)