diff --git a/autogalaxy/cosmology/model.py b/autogalaxy/cosmology/model.py
index 98e13847..f3be5dfa 100644
--- a/autogalaxy/cosmology/model.py
+++ b/autogalaxy/cosmology/model.py
@@ -574,15 +574,18 @@ def angular_diameter_distance_kpc_z1z2(
         - Dark energy equation of state constant w0
 
         Results are cached keyed on (z1, z2, n_steps) to avoid redundant
-        Simpson integrations for repeated redshift pairs.
-        """
-        cache = getattr(self, "_dist_cache", None)
-        if cache is None:
-            cache = {}
-            self._dist_cache = cache
-        key = (float(z1), float(z2), n_steps)
-        if key in cache:
-            return xp.asarray(cache[key])
+        Simpson integrations for repeated redshift pairs. Cache is only used
+        on the NumPy path — JAX abstract tracers cannot be converted to float
+        and JAX handles its own caching via JIT compilation.
+        """
+        if xp is np:
+            cache = getattr(self, "_dist_cache", None)
+            if cache is None:
+                cache = {}
+                self._dist_cache = cache
+            key = (float(z1), float(z2), n_steps)
+            if key in cache:
+                return cache[key]
 
         # Ensure odd number of samples for Simpson (safe: n_steps is a Python int)
         if (n_steps % 2) == 0:
@@ -650,7 +653,8 @@ def E_local(z):
 
         result = xp.where(same, xp.asarray(0.0), Da_kpc)
 
-        self._dist_cache[key] = float(result)
+        if xp is np:
+            self._dist_cache[key] = result
 
         return result