diff --git a/tests/renderer/test_renderer.py b/tests/renderer/test_renderer.py
index aa20324064fb2a154ea80cc6f488ba390546f1c9..ef080ea15d9abae869e0adc8a7d02b5f99b1c5bc 100644
--- a/tests/renderer/test_renderer.py
+++ b/tests/renderer/test_renderer.py
@@ -675,6 +675,8 @@ def test_custom_ls_output(
     # TODO: revert once BASOP is brought up-to-date
     if in_fmt in INPUT_FORMATS_MASA:
         pytest.skip("MASA to custom LS not supported on ivas-float-update yet")
+    if in_fmt in INPUT_FORMATS_ISM and out_fmt == "t_design_4":
+        pytest.skip("ISMx + t_design_4 skipped until bug in BASOP is fixed")
     run_renderer(
         record_property,
         props_to_record,