diff --git a/timm/models/swin_transformer_v2.py b/timm/models/swin_transformer_v2.py
index cddb68a0..9d2ad633 100644
--- a/timm/models/swin_transformer_v2.py
+++ b/timm/models/swin_transformer_v2.py
@@ -279,7 +279,7 @@ class SwinTransformerV2Block(nn.Module):
         else:
             attn_mask = None
 
-        self.register_buffer("attn_mask", attn_mask)
+        self.register_buffer("attn_mask", attn_mask, persistent=False)
 
     def _calc_window_shift(self, target_window_size, target_shift_size) -> Tuple[Tuple[int, int], Tuple[int, int]]:
         target_window_size = to_2tuple(target_window_size)
@@ -616,11 +616,12 @@ def checkpoint_filter_fn(state_dict, model):
     out_dict = {}
     import re
     for k, v in state_dict.items():
-        if any([n in k for n in ('relative_position_index', 'relative_coords_table')]):
+        if any([n in k for n in ('relative_position_index', 'relative_coords_table', 'attn_mask')]):
             continue  # skip buffers that should not be persistent
         k = re.sub(r'layers.(\d+).downsample', lambda x: f'layers.{int(x.group(1)) + 1}.downsample', k)
         k = k.replace('head.', 'head.fc.')
         out_dict[k] = v
+      
     return out_dict