diff --git a/torchao/prototype/mx_formats/kernels.py b/torchao/prototype/mx_formats/kernels.py
index 671186c7c7..265d890847 100644
--- a/torchao/prototype/mx_formats/kernels.py
+++ b/torchao/prototype/mx_formats/kernels.py
@@ -881,7 +881,10 @@ def _get_mxfp8_quant_autotune_configs():
         # can be improved in the future.
         results = []
         for ROW_TILE_SIZE in (128, 256, 512):
-            for COL_TILE_SIZE in (128, 256, 512):
+            # TODO: we can't use 512 for COL_TILE_SIZE.
+            # This is likely a triton bug, tracked in
+            # https://github.com/pytorch/ao/issues/3362
+            for COL_TILE_SIZE in (128, 256):
                 for num_warps in (4, 8):
                     for num_stages in (2, 3):
                         config = triton.Config(