diff --git a/commit-graph.c b/commit-graph.c
index fdd1c4fa7c..328ab06fd4 100644
--- a/commit-graph.c
+++ b/commit-graph.c
@@ -203,7 +203,8 @@ static int commit_graph_compatible(struct repository *r)
 	}
 
 	prepare_commit_graft(r);
-	if (r->parsed_objects && r->parsed_objects->grafts_nr)
+	if (r->parsed_objects &&
+	    (r->parsed_objects->grafts_nr || r->parsed_objects->substituted_parent))
 		return 0;
 	if (is_repository_shallow(r))
 		return 0;
diff --git a/commit.c b/commit.c
index 43d29a800d..7128895c3a 100644
--- a/commit.c
+++ b/commit.c
@@ -423,6 +423,8 @@ int parse_commit_buffer(struct repository *r, struct commit *item, const void *b
 	pptr = &item->parents;
 
 	graft = lookup_commit_graft(r, &item->object.oid);
+	if (graft)
+		r->parsed_objects->substituted_parent = 1;
 	while (bufptr + parent_entry_len < tail && !memcmp(bufptr, "parent ", 7)) {
 		struct commit *new_parent;
 
diff --git a/object.h b/object.h
index 38dc2d5a6c..96a2105859 100644
--- a/object.h
+++ b/object.h
@@ -25,6 +25,7 @@ struct parsed_object_pool {
 	char *alternate_shallow_file;
 
 	int commit_graft_prepared;
+	int substituted_parent;
 
 	struct buffer_slab *buffer_slab;
 };
diff --git a/t/t5537-fetch-shallow.sh b/t/t5537-fetch-shallow.sh
index d427a2d7f7..a55202d2d3 100755
--- a/t/t5537-fetch-shallow.sh
+++ b/t/t5537-fetch-shallow.sh
@@ -81,6 +81,20 @@ test_expect_success 'fetch --unshallow from shallow clone' '
 	)
 '
 
+test_expect_success 'fetch --unshallow from a full clone' '
+	git clone --no-local --depth=2 .git shallow3 &&
+	(
+	cd shallow3 &&
+	git log --format=%s >actual &&
+	test_write_lines 4 3 >expect &&
+	test_cmp expect actual &&
+	git -c fetch.writeCommitGraph fetch --unshallow &&
+	git log origin/master --format=%s >actual &&
+	test_write_lines 4 3 2 1 >expect &&
+	test_cmp expect actual
+	)
+'
+
 test_expect_success 'fetch something upstream has but hidden by clients shallow boundaries' '
 	# the blob "1" is available in .git but hidden by the
 	# shallow2/.git/shallow and it should be resent