diff --git a/src/libknot/rrset.c b/src/libknot/rrset.c
index 3fe3c93a45223d934a07455b526a78ea2291daec..55bcbdcc5a54ddeaaedf3a03503943d03bea4bc5 100644
--- a/src/libknot/rrset.c
+++ b/src/libknot/rrset.c
@@ -1359,8 +1359,8 @@ int knot_rrset_equal(const knot_rrset_t *r1,
 	return res;
 }
 
-int knot_rrset_deep_copy(const knot_rrset_t *from, knot_rrset_t **to,
-                         int copy_rdata_dnames)
+int knot_rrset_deep_copy_no_sig(const knot_rrset_t *from, knot_rrset_t **to,
+                                int copy_rdata_dnames)
 {
 	if (from == NULL || to == NULL) {
 		return KNOT_EINVAL;
@@ -1382,16 +1382,7 @@ int knot_rrset_deep_copy(const knot_rrset_t *from, knot_rrset_t **to,
 	(*to)->ttl = from->ttl;
 	(*to)->type = from->type;
 	(*to)->rdata_count = from->rdata_count;
-	if (from->rrsigs != NULL) {
-		int ret = knot_rrset_deep_copy(from->rrsigs, &(*to)->rrsigs,
-		                           copy_rdata_dnames);
-		if (ret != KNOT_EOK) {
-			knot_rrset_deep_free(to, 1, 0);
-			return ret;
-		}
-	} else {
-		(*to)->rrsigs = NULL;
-	}
+	(*to)->rrsigs = NULL;
 
 	/* Just copy arrays - actual data + indices. */
 	(*to)->rdata = xmalloc(rrset_rdata_size_total(from));
@@ -1437,6 +1428,24 @@ dbg_rrset_exec_detail(
 	return KNOT_EOK;
 }
 
+
+int knot_rrset_deep_copy(const knot_rrset_t *from, knot_rrset_t **to,
+                         int copy_rdata_dnames)
+{
+	int result = knot_rrset_deep_copy_no_sig(from, to, copy_rdata_dnames);
+
+	if (result == KNOT_EOK && from->rrsigs != NULL) {
+		result = knot_rrset_deep_copy_no_sig(from->rrsigs,
+		                                     &(*to)->rrsigs,
+		                                     copy_rdata_dnames);
+		if (result != KNOT_EOK) {
+			knot_rrset_deep_free(to, 1, 0);
+		}
+	}
+
+	return result;
+}
+
 /*----------------------------------------------------------------------------*/
 
 int knot_rrset_shallow_copy(const knot_rrset_t *from, knot_rrset_t **to)
diff --git a/src/libknot/rrset.h b/src/libknot/rrset.h
index 88bfdcfffb90d362ef237f1e7ba45abe9c0a7860..3b97f2acd6798fee106e4ae465fc49c723f7a764 100644
--- a/src/libknot/rrset.h
+++ b/src/libknot/rrset.h
@@ -285,6 +285,9 @@ int knot_rrset_equal(const knot_rrset_t *r1,
 int knot_rrset_deep_copy(const knot_rrset_t *from, knot_rrset_t **to,
                          int copy_rdata_dnames);
 
+int knot_rrset_deep_copy_no_sig(const knot_rrset_t *from, knot_rrset_t **to,
+                                int copy_rdata_dnames);
+
 int knot_rrset_shallow_copy(const knot_rrset_t *from, knot_rrset_t **to);
 
 /*! \brief Does round-robin rotation of the RRSet.
diff --git a/src/libknot/zone/zone-diff.c b/src/libknot/zone/zone-diff.c
index c62ca7a95cc1826f5acf78ac48550cb429eaac15..361f5fb9baf4717537a755dd90a50ba1ab4c885e 100644
--- a/src/libknot/zone/zone-diff.c
+++ b/src/libknot/zone/zone-diff.c
@@ -109,23 +109,19 @@ static int knot_zone_diff_load_soas(const knot_zone_contents_t *zone1,
 
 	assert(changeset);
 
-	ret = knot_rrset_deep_copy(soa_rrset1, &changeset->soa_from, 1);
+	ret = knot_rrset_deep_copy_no_sig(soa_rrset1, &changeset->soa_from, 1);
 	if (ret != KNOT_EOK) {
 		dbg_zonediff("zone_diff: load_soas: Cannot copy RRSet.\n");
 		return ret;
 	}
 
-	/* We MUST NOT save this RRSIG. */
-	knot_rrset_deep_free(&changeset->soa_from->rrsigs, 1, 1);
-	assert(changeset->soa_from->rrsigs == NULL);
-
-	ret = knot_rrset_deep_copy(soa_rrset2, &changeset->soa_to, 1);
+	ret = knot_rrset_deep_copy_no_sig(soa_rrset2, &changeset->soa_to, 1);
 	if (ret != KNOT_EOK) {
 		dbg_zonediff("zone_diff: load_soas: Cannot copy RRSet.\n");
 		return ret;
 	}
 
-	knot_rrset_deep_free(&changeset->soa_to->rrsigs, 1, 1);
+	assert(changeset->soa_from->rrsigs == NULL);
 	assert(changeset->soa_to->rrsigs == NULL);
 
 	changeset->serial_from = soa_serial1;
@@ -158,14 +154,11 @@ static int knot_zone_diff_changeset_add_rrset(knot_changeset_t *changeset,
 	knot_rrset_dump(rrset);
 
 	knot_rrset_t *rrset_copy = NULL;
-	int ret = knot_rrset_deep_copy(rrset, &rrset_copy, 1);
+	int ret = knot_rrset_deep_copy_no_sig(rrset, &rrset_copy, 1);
 	if (ret != KNOT_EOK) {
 		dbg_zonediff("zone_diff: add_rrset: Cannot copy RRSet.\n");
 		return ret;
 	}
-	if (rrset_copy->rrsigs != NULL) {
-		knot_rrset_deep_free(&rrset_copy->rrsigs, 1, 1);
-	}
 	assert(knot_rrset_rrsigs(rrset_copy) == NULL);
 
 	ret = knot_changeset_add_new_rr(changeset, rrset_copy,
@@ -205,14 +198,11 @@ static int knot_zone_diff_changeset_remove_rrset(knot_changeset_t *changeset,
 	knot_rrset_dump(rrset);
 
 	knot_rrset_t *rrset_copy = NULL;
-	int ret = knot_rrset_deep_copy(rrset, &rrset_copy, 1);
+	int ret = knot_rrset_deep_copy_no_sig(rrset, &rrset_copy, 1);
 	if (ret != KNOT_EOK) {
 		dbg_zonediff("zone_diff: remove_rrset: Cannot copy RRSet.\n");
 		return ret;
 	}
-	if (rrset_copy->rrsigs != NULL) {
-		knot_rrset_deep_free(&rrset_copy->rrsigs, 1, 1);
-	}
 	assert(knot_rrset_rrsigs(rrset_copy) == NULL);
 
 	ret = knot_changeset_add_new_rr(changeset, rrset_copy,