diff --git a/src/sample.c b/src/sample.c
index 10749c0e2..4253dd15e 100644
--- a/src/sample.c
+++ b/src/sample.c
@@ -839,9 +839,6 @@ struct sample *sample_process(struct proxy *px, struct session *l4, void *l7,
 	if (!expr->fetch->process(px, l4, l7, opt, expr->arg_p, p, expr->fetch->kw))
 		return NULL;
 
-	if ((p->flags & SMP_F_MAY_CHANGE) && !(opt & SMP_OPT_FINAL))
-		return NULL; /* we can only use stable samples */
-
 	list_for_each_entry(conv_expr, &expr->conv_exprs, list) {
 		/* we want to ensure that p->type can be casted into
 		 * conv_expr->conv->in_type. We have 3 possibilities :
diff --git a/src/stick_table.c b/src/stick_table.c
index 45e6118fe..9a3e855a1 100644
--- a/src/stick_table.c
+++ b/src/stick_table.c
@@ -615,6 +615,9 @@ struct stktable_key *stktable_fetch_key(struct stktable *t, struct proxy *px, st
 	if (!smp)
 		return NULL;
 
+	if ((smp->flags & SMP_F_MAY_CHANGE) && !(opt & SMP_OPT_FINAL))
+		return NULL; /* we can only use stable samples */
+
 	if (!sample_to_key[smp->type][t->type])
 		return NULL;