diff --git a/python/sglang/srt/arg_groups/overrides.py b/python/sglang/srt/arg_groups/overrides.py
index 4d175a47a..bbb775722 100644
--- a/python/sglang/srt/arg_groups/overrides.py
+++ b/python/sglang/srt/arg_groups/overrides.py
@@ -1796,6 +1796,9 @@ def _fa4_page_constraint(view: Any) -> dict:
         # CUTLASS kernel aborts on at page_size>1. That path only works at
         # page_size==1, so skip the 128 auto-force for it and keep the default.
         and (view.speculative_eagle_topk or 0) <= 1
+        # The full prefill CUDA graph runs the FA backend at page_size==1 only
+        # (#27988), so skip the 128 auto-force for it and keep the default.
+        and view.cuda_graph_config.prefill.backend != Backend.FULL
     ):
         logger.warning(
             f"FA4 backend only supports page size 128 for non-MLA model architectures, changing page_size from {view.page_size} to 128."