From 5cd7bcb5b49781e8d48dfc214b7092d2586042fd Mon Sep 17 00:00:00 2001
From: dcherian <deepak@cherian.net>
Date: Fri, 4 Nov 2022 18:23:39 -0600
Subject: [PATCH] Better fix

---
 flox/core.py | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/flox/core.py b/flox/core.py
index acd75a772..e1e7dc039 100644
--- a/flox/core.py
+++ b/flox/core.py
@@ -1350,7 +1350,10 @@ def dask_groupby_agg(
                         aggregate=partial(aggregate, expected_groups=index, reindex=True),
                     )
                 )
-                groups_.append(cohort)
+                # This is done because pandas promotes to 64-bit types when an Index is created
+                # So we use the index to generate the return value for consistency with "map-reduce"
+                # This is important on windows
+                groups_.append(index.values)
 
             reduced = dask.array.concatenate(reduced_, axis=-1)
             groups = (np.concatenate(groups_),)