diff --git a/flytekit/core/python_auto_container.py b/flytekit/core/python_auto_container.py
index 0e3dd5bda8..ace756ca0b 100644
--- a/flytekit/core/python_auto_container.py
+++ b/flytekit/core/python_auto_container.py
@@ -467,10 +467,16 @@ def get_registerable_container_image(img: Optional[Union[str, ImageSpec]], cfg:
             if img_cfg is None:
                 raise AssertionError(f"Image Config with name {name} not found in the configuration")
             if attr == "version":
-                if img_cfg.version is not None:
-                    img = img.replace(replace_group, img_cfg.version)
+                version = img_cfg.version if img_cfg.version is not None else cfg.default_image.version
+                if ":" in version:
+                    # version is a digest (e.g. sha256:...) — needs @ separator, not :
+                    colon_prefixed = f":{replace_group}"
+                    if colon_prefixed in img:
+                        img = img.replace(colon_prefixed, f"@{version}")
+                    else:
+                        img = img.replace(replace_group, version)
                 else:
-                    img = img.replace(replace_group, cfg.default_image.version)
+                    img = img.replace(replace_group, version)
             elif attr == "fqn":
                 img = img.replace(replace_group, img_cfg.fqn)
             elif attr == "":
diff --git a/tests/flytekit/unit/core/test_python_function_task.py b/tests/flytekit/unit/core/test_python_function_task.py
index 427e3bd774..b2e4d9c1b9 100644
--- a/tests/flytekit/unit/core/test_python_function_task.py
+++ b/tests/flytekit/unit/core/test_python_function_task.py
@@ -58,7 +58,13 @@ def test_container_image_conversion(mock_image_spec_builder):
         fqn="xyz.com/other5",
         tag="tag5"
     )
-    cfg = ImageConfig(default_image=default_img, images=[default_img, other_img, other_img2, other_img3, other_img4, other_img5])
+    # Simulates _parse_image_identifier("xyz.com/other6:tag6@sha256:...") where the tag is baked into fqn
+    other_img6 = Image(
+        name="other6",
+        fqn="xyz.com/other6:tag6",
+        digest="sha256:26c68657ccce2cb0a31b330cb0be2b5e108d467f641c62e13ab40cbec258c68d",
+    )
+    cfg = ImageConfig(default_image=default_img, images=[default_img, other_img, other_img2, other_img3, other_img4, other_img5, other_img6])
     assert get_registerable_container_image(None, cfg) == "xyz.com/abc:tag1"
     assert get_registerable_container_image("", cfg) == "xyz.com/abc:tag1"
     assert get_registerable_container_image("abc", cfg) == "abc"
@@ -78,6 +84,16 @@ def test_container_image_conversion(mock_image_spec_builder):
         get_registerable_container_image("{{.image.other2.fqn}}@{{.image.other2.version}}", cfg)
         == "xyz.com/other2@sha256:26c68657ccce2cb0a31b330cb0be2b5e108d467f641c62e13ab40cbec258c68d"
     )
+    # Digest image with : separator in template should be fixed to @
+    assert (
+        get_registerable_container_image("{{.image.other2.fqn}}:{{.image.other2.version}}", cfg)
+        == "xyz.com/other2@sha256:26c68657ccce2cb0a31b330cb0be2b5e108d467f641c62e13ab40cbec258c68d"
+    )
+    # repo:tag@sha256:digest — fqn already contains the tag, digest needs @ separator
+    assert (
+        get_registerable_container_image("{{.image.other6.fqn}}:{{.image.other6.version}}", cfg)
+        == "xyz.com/other6:tag6@sha256:26c68657ccce2cb0a31b330cb0be2b5e108d467f641c62e13ab40cbec258c68d"
+    )
     assert (
         get_registerable_container_image("{{.image.other3.fqn}}:{{.image.other3.version}}", cfg)
         == "xyz.com/other3:tag1"