diff --git a/commit.c b/commit.c
index 3a54e4db0d..cc03a93036 100644
--- a/commit.c
+++ b/commit.c
@@ -595,7 +595,8 @@ int repo_parse_commit_internal(struct repository *r,
 	}
 
 	ret = parse_commit_buffer(r, item, buffer, size, 0);
-	if (save_commit_buffer && !ret) {
+	if (save_commit_buffer && !ret &&
+	    !get_cached_commit_buffer(r, item, NULL)) {
 		set_commit_buffer(r, item, buffer, size);
 		return 0;
 	}
diff --git a/t/t5539-fetch-http-shallow.sh b/t/t5539-fetch-http-shallow.sh
index 3ea75d34ca..82fe09d0a9 100755
--- a/t/t5539-fetch-http-shallow.sh
+++ b/t/t5539-fetch-http-shallow.sh
@@ -5,6 +5,7 @@ test_description='fetch/clone from a shallow clone over http'
 GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME=main
 export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 . "$TEST_DIRECTORY"/lib-httpd.sh
 start_httpd