diff --git a/src/pgduckdb_metadata_cache.cpp b/src/pgduckdb_metadata_cache.cpp
index 43edc4eb..8031cdf4 100644
--- a/src/pgduckdb_metadata_cache.cpp
+++ b/src/pgduckdb_metadata_cache.cpp
@@ -62,7 +62,10 @@ InvalidateCaches(Datum arg, int cache_id, uint32 hash_value) {
 		return;
 	}
 	cache.valid = false;
-	list_free(cache.duckdb_only_functions);
+	if (cache.installed) {
+		list_free(cache.duckdb_only_functions);
+		cache.duckdb_only_functions = NIL;
+	}
 }
 
 /*
diff --git a/test/regression/expected/basic.out b/test/regression/expected/basic.out
index 3bfa1c1a..fc407602 100644
--- a/test/regression/expected/basic.out
+++ b/test/regression/expected/basic.out
@@ -43,3 +43,7 @@ SET duckdb.max_threads_per_query TO default;
 SET client_min_messages TO default;
 DROP TABLE t;
 DROP TABLE empty;
+-- Check that DROP / CREATE extension works
+DROP EXTENSION pg_duckdb;
+CREATE EXTENSION pg_duckdb;
+WARNING:  To actually execute queries using DuckDB you need to run "SET duckdb.execution TO true;"
diff --git a/test/regression/sql/basic.sql b/test/regression/sql/basic.sql
index e8709e32..d32d3f0a 100644
--- a/test/regression/sql/basic.sql
+++ b/test/regression/sql/basic.sql
@@ -20,3 +20,8 @@ SET client_min_messages TO default;
 
 DROP TABLE t;
 DROP TABLE empty;
+
+-- Check that DROP / CREATE extension works
+
+DROP EXTENSION pg_duckdb;
+CREATE EXTENSION pg_duckdb;