diff --git a/monai/data/grid_dataset.py b/monai/data/grid_dataset.py
index 03b757911d..2f397018e7 100644
--- a/monai/data/grid_dataset.py
+++ b/monai/data/grid_dataset.py
@@ -313,7 +313,7 @@ def _load_cache_item(self, idx: int):
         patch_cache, other_cache = [], []
         for patch, *others in self.patch_iter(item):
             if self.first_random is not None:
-                patch = self.patch_transform(patch, end=self.first_random, threading=True)
+                patch = self.patch_transform(patch, end=self.first_random, threading=True)  # type: ignore
 
             if self.as_contiguous:
                 patch = convert_to_contiguous(patch, memory_format=torch.contiguous_format)