diff --git a/jax_profiling/imaging/pixelization_sparse_cpu.py b/jax_profiling/imaging/pixelization_sparse_cpu.py
index 2778bb8..8425684 100644
--- a/jax_profiling/imaging/pixelization_sparse_cpu.py
+++ b/jax_profiling/imaging/pixelization_sparse_cpu.py
@@ -14,8 +14,10 @@
   ``pixelization.py`` to within ``rtol=1e-4`` (asserted at the bottom).
 * ``fit_sparse``    — ``FitImaging(xp=np)`` on a dataset with an attached
   CPU sparse operator (``apply_sparse_operator_cpu()``). Its ``log_evidence``
-  is reported next to the gold reference but *not* asserted — the script's
-  job is to surface any divergence, not hide it.
+  is also asserted to match ``fit_no_sparse`` (within ``rtol=1e-4``) so this
+  script doubles as a CPU-sparse regression test. (PyAutoArray PR #296 fixed
+  an out-of-bounds read in ``psf_precision_value_from`` that previously made
+  the sparse path return ``NaN`` for masks touching the noise-map boundary.)
 
 Per-step timings are eager-only: numba functions are compiled on first call
 and reused on subsequent calls, so each section reports a first-call cost
@@ -668,10 +670,11 @@ def _log_evidence():
 # point — they share the same mathematical formulation and only differ in
 # their array backend. Asserting parity catches drift on either side.
 #
-# The sparse path is intentionally NOT asserted: this script is a diagnostic
-# for surfacing any divergence between sparse and non-sparse, so failing on
-# divergence would defeat its purpose. The numbers above + the JSON output
-# are the evidence the user needs to debug the sparse path.
+# Both paths are asserted post-fix (PyAutoArray PR #296 fixed the OOB read in
+# psf_precision_value_from). Keeping the sparse-path assertion here means the
+# script doubles as a regression test: if the sparse-CPU bug recurs, this
+# script will fail loudly instead of silently writing a "false" flag into the
+# JSON.
 
 np.testing.assert_allclose(
     log_evidence_no_sparse,
@@ -688,16 +691,20 @@ def _log_evidence():
     f"log_evidence matches JAX reference {EXPECTED_LOG_EVIDENCE_HST:.6f}"
 )
 
-if sparse_matches_non_sparse:
-    print(
-        f"  Sparse path also agrees with non-sparse to rtol=1e-4 "
-        f"(observed rtol = {sparse_vs_non_sparse_rtol:.3e})."
-    )
-else:
-    print(
-        f"  *** SPARSE PATH DIVERGES from non-sparse: observed rtol = "
-        f"{sparse_vs_non_sparse_rtol:.3e} (>= 1e-4). "
-        f"This script's purpose is to surface this divergence; investigate "
-        f"the sparse-CPU path in PyAutoArray/autoarray/inversion/inversion/"
-        f"imaging_numba/."
-    )
+np.testing.assert_allclose(
+    log_evidence_sparse,
+    log_evidence_no_sparse,
+    rtol=1e-4,
+    err_msg=(
+        f"imaging/pixelization_sparse_cpu[{instrument}]: regression — CPU "
+        f"sparse-operator log_evidence diverges from non-sparse "
+        f"(sparse={log_evidence_sparse}, non_sparse={log_evidence_no_sparse}, "
+        f"observed rtol={sparse_vs_non_sparse_rtol:.3e}). Likely regression "
+        f"in PyAutoArray/autoarray/inversion/inversion/imaging_numba/."
+    ),
+)
+print(
+    f"  Sparse regression assertion PASSED: "
+    f"sparse log_evidence matches non-sparse (rtol = "
+    f"{sparse_vs_non_sparse_rtol:.3e})."
+)
diff --git a/jax_profiling/imaging/results/pixelization_sparse_cpu_likelihood_summary_hst_v2026.5.1.4.json b/jax_profiling/imaging/results/pixelization_sparse_cpu_likelihood_summary_hst_v2026.5.1.4.json
index a37f352..684b0ce 100644
--- a/jax_profiling/imaging/results/pixelization_sparse_cpu_likelihood_summary_hst_v2026.5.1.4.json
+++ b/jax_profiling/imaging/results/pixelization_sparse_cpu_likelihood_summary_hst_v2026.5.1.4.json
@@ -13,23 +13,23 @@
     "source_pixels": 784
   },
   "steps": {
-    "Ray-trace grids": 0.007880670000304235,
-    "Lens light images (pre-PSF)": 0.004302589999861084,
-    "Blurred image (PSF convolution)": 0.01615301999991061,
-    "Profile-subtracted image": 1.0900000052060933e-05,
-    "Inversion setup (steps 4-7 combined)": 1.9999999494757505e-06,
-    "Data vector (D)": 0.05178085000006831,
-    "Curvature matrix (F)": 0.3827769700001227,
-    "Regularization matrix (H)": 0.04594268000000738,
-    "Regularized reconstruction": 0.456709669999691,
-    "Mapped recon + log evidence": 0.422671039999841
+    "Ray-trace grids": 0.010212379999575204,
+    "Lens light images (pre-PSF)": 0.005444229999557138,
+    "Blurred image (PSF convolution)": 0.024003369999991264,
+    "Profile-subtracted image": 1.8070000078296288e-05,
+    "Inversion setup (steps 4-7 combined)": 2.540000423323363e-06,
+    "Data vector (D)": 0.06494419000009657,
+    "Curvature matrix (F)": 0.37986498000027497,
+    "Regularization matrix (H)": 0.049308830000518354,
+    "Regularized reconstruction": 0.43148055000056046,
+    "Mapped recon + log evidence": 0.5270483899999817
   },
-  "total_step_by_step": 1.3882303899998079,
-  "fit_no_sparse_full_likelihood_per_call": 3.598550679999607,
+  "total_step_by_step": 1.4923275300010572,
+  "fit_no_sparse_full_likelihood_per_call": 3.6985298600004173,
   "log_evidence_no_sparse": 26232.068573757562,
-  "log_evidence_sparse": NaN,
+  "log_evidence_sparse": 26232.06854278734,
   "log_evidence_jax_expected": 26232.068573757562,
-  "delta_sparse_minus_no_sparse": NaN,
-  "delta_sparse_minus_jax_expected": NaN,
-  "sparse_matches_non_sparse_rtol_1em4": false
+  "delta_sparse_minus_no_sparse": -3.0970222724135965e-05,
+  "delta_sparse_minus_jax_expected": -3.0970222724135965e-05,
+  "sparse_matches_non_sparse_rtol_1em4": true
 }
\ No newline at end of file
diff --git a/jax_profiling/imaging/results/pixelization_sparse_cpu_likelihood_summary_hst_v2026.5.1.4.png b/jax_profiling/imaging/results/pixelization_sparse_cpu_likelihood_summary_hst_v2026.5.1.4.png
index 734cfd4..a1e308e 100644
Binary files a/jax_profiling/imaging/results/pixelization_sparse_cpu_likelihood_summary_hst_v2026.5.1.4.png and b/jax_profiling/imaging/results/pixelization_sparse_cpu_likelihood_summary_hst_v2026.5.1.4.png differ