diff --git a/dagger/pipeline.go b/dagger/pipeline.go
index 271dbb5d..c8f76b81 100644
--- a/dagger/pipeline.go
+++ b/dagger/pipeline.go
@@ -385,13 +385,10 @@ func (p *Pipeline) Exec(ctx context.Context, op *compiler.Value, st llb.State) (
 	}
 
 	// always?
-	// FIXME: initialize once for an entire compute job, to avoid cache misses
 	if cmd.Always {
-		cacheBuster, err := randomID(8)
-		if err != nil {
-			return st, err
-		}
-		opts = append(opts, llb.AddEnv("DAGGER_CACHEBUSTER", cacheBuster))
+		// FIXME: also disables persistent cache directories
+		// There's an ongoing proposal that would fix this: https://github.com/moby/buildkit/issues/1213
+		opts = append(opts, llb.IgnoreCache)
 	}
 	// mounts
 	if mounts := op.Lookup("mount"); mounts.Exists() {
diff --git a/dagger/utils.go b/dagger/utils.go
deleted file mode 100644
index 211516c8..00000000
--- a/dagger/utils.go
+++ /dev/null
@@ -1,15 +0,0 @@
-package dagger
-
-import (
-	"crypto/rand"
-	"fmt"
-)
-
-func randomID(size int) (string, error) {
-	b := make([]byte, size)
-	_, err := rand.Read(b)
-	if err != nil {
-		return "", err
-	}
-	return fmt.Sprintf("%x", b), nil
-}
diff --git a/stdlib/aws/elb/elb.cue b/stdlib/aws/elb/elb.cue
index c5077065..cd6a0851 100644
--- a/stdlib/aws/elb/elb.cue
+++ b/stdlib/aws/elb/elb.cue
@@ -19,9 +19,7 @@ import (
 	out: string
 
 	aws.#Script & {
-		// FIXME: we should not rely on the cache for this but it's being
-		// executed several times if enabled: https://github.com/dagger/dagger/issues/42
-		// always: true
+		always: true
 
 		files: {
 			"/inputs/listenerArn": listenerArn
diff --git a/stdlib/dagger/op/op.cue b/stdlib/dagger/op/op.cue
index 6bdcc8a4..92ec4c53 100644
--- a/stdlib/dagger/op/op.cue
+++ b/stdlib/dagger/op/op.cue
@@ -45,6 +45,7 @@ package op
 	do: "exec"
 	args: [...string]
 	env?: [string]: string
+	// `true` means also ignoring the mount cache volumes
 	always?: true | *false
 	dir:     string | *"/"
 	mount: [string]: "tmpfs" | "cache" | {from: _, path: string | *"/"}
diff --git a/tests/compute/success/exec-nocache/main.cue b/tests/compute/success/exec-nocache/main.cue
new file mode 100644
index 00000000..fb9eef6b
--- /dev/null
+++ b/tests/compute/success/exec-nocache/main.cue
@@ -0,0 +1,25 @@
+package main
+
+import (
+	"dagger.io/alpine"
+	"dagger.io/dagger/op"
+)
+
+rand: {
+	string
+
+	#up: [
+		op.#Load & {from: alpine.#Image},
+		op.#Exec & {
+			always: true
+			args: ["sh", "-c", """
+				tr -dc A-Za-z0-9 </dev/urandom | head -c 13 > /id
+				"""]
+		},
+		op.#Export & {source: "/id"},
+	]
+}
+
+// If rand is executed twice, cue won't validate
+ref1: rand
+ref2: ref1
diff --git a/tests/test-compute.sh b/tests/test-compute.sh
index 324d9a64..7d5c22e2 100644
--- a/tests/test-compute.sh
+++ b/tests/test-compute.sh
@@ -35,6 +35,8 @@ test::compute::simple(){
       "$dagger" "${DAGGER_BINARY_ARGS[@]}" compute "$d"/compute/success/overload/flat
   test::one "Compute: overloading #Component should work" --exit=0  \
       "$dagger" "${DAGGER_BINARY_ARGS[@]}" compute "$d"/compute/success/overload/wrapped
+  test::one "Compute: Disabling the cache on exec should not compute twice when referenced by another key" --exit=0  \
+      "$dagger" "${DAGGER_BINARY_ARGS[@]}" compute "$d"/compute/success/exec-nocache
 }
 
 test::compute::dependencies(){