diff --git a/src/hb-ot-layout-gsubgpos.hh b/src/hb-ot-layout-gsubgpos.hh
index f82097680..abc60e68e 100644
--- a/src/hb-ot-layout-gsubgpos.hh
+++ b/src/hb-ot-layout-gsubgpos.hh
@@ -116,7 +116,8 @@ struct hb_closure_context_t :
 	}
       }
 
-      done_lookups_glyph_set->get (lookup_index)->clear ();
+      if (done_lookups_glyph_set->get (lookup_index)->get_population ())
+        done_lookups_glyph_set->get (lookup_index)->clear ();
     }
 
     hb_set_t *covered_glyph_set = done_lookups_glyph_set->get (lookup_index);
diff --git a/test/fuzzing/fonts/clusterfuzz-testcase-minimized-hb-subset-fuzzer-5617065093365760 b/test/fuzzing/fonts/clusterfuzz-testcase-minimized-hb-subset-fuzzer-5617065093365760
new file mode 100644
index 000000000..590e6fc39
Binary files /dev/null and b/test/fuzzing/fonts/clusterfuzz-testcase-minimized-hb-subset-fuzzer-5617065093365760 differ