diff --git a/scripts/nvx_tools/release.py b/scripts/nvx_tools/release.py
index e5766981..393af036 100644
--- a/scripts/nvx_tools/release.py
+++ b/scripts/nvx_tools/release.py
@@ -213,6 +213,7 @@ def _latest_release_asset(
                 and asset_pattern.fullmatch(name) is not None
                 and isinstance(asset_url, str)
                 and isinstance(size, int)
+                and not isinstance(size, bool)
             ):
                 return _ReleaseAsset(tag, name, asset_url, size)
     raise ScriptError(f"no GitHub release contains an NVX package for {platform}")
diff --git a/scripts/test_nvx_tools.py b/scripts/test_nvx_tools.py
index f8f7eeb2..aab6088b 100644
--- a/scripts/test_nvx_tools.py
+++ b/scripts/test_nvx_tools.py
@@ -7284,6 +7284,11 @@ def test_selects_latest_matching_prerelease_asset(self):
                 "prerelease": True,
                 "tag_name": "v1.2.3-dev.abc123",
                 "assets": [
+                    {
+                        "name": "nvx-invalid-linux-kvm.tar.gz",
+                        "url": "https://api.example.invalid/invalid",
+                        "size": True,
+                    },
                     {
                         "name": "nvx-1.2.3-windows-whp.zip",
                         "url": "https://api.example.invalid/windows",