diff --git a/whatformat/util/whatdateformat.py b/whatformat/util/whatdateformat.py
index 0b39f321279fb7f5c95093e1cf7ca65e16bfd784..c1c20cfd1a3976563a836e9b0c764ae0c43565f9 100644
--- a/whatformat/util/whatdateformat.py
+++ b/whatformat/util/whatdateformat.py
@@ -73,9 +73,9 @@ def _remove_extra_nlz(combinations) -> Iterator[List[str]]:
     for variant in combinations:
         is_duplicate = False
         for i, token in enumerate(variant):
-            if '-' in token:
+            if '%-' in token:
                 with_zero = (variant[:i] +
-                             (token.replace('-', ''),) +
+                             (token.replace('%-', '%'),) +
                              variant[(i + 1):])
                 if with_zero in combinations:
                     is_duplicate = True