diff --git a/.github/workflows/pull_request.yaml b/.github/workflows/pull_request.yaml
index 7ee343d..e9aec8b 100644
--- a/.github/workflows/pull_request.yaml
+++ b/.github/workflows/pull_request.yaml
@@ -34,7 +34,11 @@ jobs:
   # result -- visible signal for the investigation -- but doesn't block this
   # workflow or PR merge readiness. Drop once the segfault is fixed.
   test_cmake_build:
-    uses: NWChemEx/.github/.github/workflows/test_nwx_cmake_build.yaml@master
+    # TEMPORARY: pinned to the macos-crash-diagnostics branch to capture
+    # dyld/Python-runtime evidence for scf-macos-pybind11-segfault.md.
+    # Revert to @master before this branch/PR is closed out -- never merge
+    # this pin.
+    uses: NWChemEx/.github/.github/workflows/test_nwx_cmake_build.yaml@macos-crash-diagnostics
     with:
       run_python_tests: "true"
       cmake_opts: "-DINTEGRATION_TESTING=ON"