diff --git a/src/picom.c b/src/picom.c
index fd693fc927..ecd09078e8 100644
--- a/src/picom.c
+++ b/src/picom.c
@@ -539,8 +539,8 @@ static bool initialize_backend(session_t *ps) {
 				} else {
 					shader->attributes = 0;
 				}
-				log_debug("Shader %s has attributes %ld", shader->key,
-				          shader->attributes);
+				log_debug("Shader %s has attributes %" PRIu64,
+				          shader->key, shader->attributes);
 			}
 		}
 
diff --git a/src/win.c b/src/win.c
index 2525d89718..fb61191638 100644
--- a/src/win.c
+++ b/src/win.c
@@ -2140,6 +2140,7 @@ static void destroy_win_finish(session_t *ps, struct win *w) {
 			assert(mw->shadow_image != NULL);
 			win_release_shadow(ps->backend_data, mw);
 		}
+		win_release_mask(ps->backend_data, mw);
 
 		// Invalidate reg_ignore of windows below this one
 		// TODO(yshui) what if next_w is not mapped??