diff --git a/Project_Model/Libs/Transformer/Classes/SpannedMasker.py b/Project_Model/Libs/Transformer/Classes/SpannedMasker.py
index 156f512..441a3d8 100644
--- a/Project_Model/Libs/Transformer/Classes/SpannedMasker.py
+++ b/Project_Model/Libs/Transformer/Classes/SpannedMasker.py
@@ -90,6 +90,11 @@ class SpannedMasker:
             SPAN_LENGTH = min(CANDIDATE_SPAN, REMAINING_MASK)
 
             for _ in range(0, SPAN_LENGTH):
+                INNER_TOKEN = sequence[mask_index]
+
+                if self.__is_illegal_token(INNER_TOKEN, forbidden_tokens):
+                    continue
+                
                 MASK[mask_index] = True
                 mask_index += 1