diff --git a/mautrix_telegram/formatter/from_telegram.py b/mautrix_telegram/formatter/from_telegram.py
index b82b1c4d..e730f3b3 100644
--- a/mautrix_telegram/formatter/from_telegram.py
+++ b/mautrix_telegram/formatter/from_telegram.py
@@ -259,7 +259,7 @@ async def _telegram_entities_to_matrix(
 
         while within_surrogate(text, relative_offset, length=length):
             relative_offset += 1
-        while within_surrogate(text, relative_offset + length, length=length):
+        while within_surrogate(text, relative_offset + entity.length, length=length):
             entity.length += 1
 
         skip_entity = False