diff --git a/src/conda_project/project.py b/src/conda_project/project.py
index 4130f68..7174b32 100644
--- a/src/conda_project/project.py
+++ b/src/conda_project/project.py
@@ -501,17 +501,23 @@ def is_consistent(self) -> bool:
         # We only include locked packages for the current platform, and don't
         # include optional dependencies (e.g. compile/build)
         lock = parse_conda_lock_file(self.lockfile)
+        current_platform_packages = [
+            p
+            for p in lock.package
+            if p.platform == current_platform() and p.category == "main"
+        ]
 
         # When an environment is installed pypi packages take precedence
         deduped_lock = dedupe_list_of_dicts(
-            lock.package, key=lambda x: x.name, keep=lambda x: x.manager == "pip"
+            current_platform_packages,
+            key=lambda x: x.name,
+            keep=lambda x: x.manager == "pip",
         )
 
         locked_pkgs = set()
         for p in deduped_lock:
-            if p.platform == current_platform() and p.category == "main":
-                hash = p.hash.md5 if p.manager == "conda" else p.hash.sha256
-                locked_pkgs.add((p.name, p.version, p.manager, hash))
+            hash = p.hash.md5 if p.manager == "conda" else p.hash.sha256
+            locked_pkgs.add((p.name, p.version, p.manager, hash))
 
         # Compare the sets
         # We can do this because the tuples are hashable. Also we don't need to
diff --git a/tests/test_install.py b/tests/test_install.py
index 4255542..2cfd930 100644
--- a/tests/test_install.py
+++ b/tests/test_install.py
@@ -48,10 +48,9 @@ def test_install_no_dependencies(project_directory_factory):
 @pytest.mark.slow
 def test_is_installed(project_directory_factory):
     env_yaml = dedent(
-        f"""\
+        """\
         name: test
         dependencies: [python=3.8]
-        platforms: [{current_platform()}]
         """
     )
     project_path = project_directory_factory(env_yaml=env_yaml)
@@ -61,12 +60,11 @@ def test_is_installed(project_directory_factory):
     assert project.default_environment.is_consistent
 
     updated_yaml = dedent(
-        f"""\
+        """\
         name: test
         dependencies:
           - python=3.8
           - requests
-        platforms: [{current_platform()}]
         """
     )