diff --git a/src/calibre/utils/matcher.c b/src/calibre/utils/matcher.c
index bf5dead056..209a7e390d 100644
--- a/src/calibre/utils/matcher.c
+++ b/src/calibre/utils/matcher.c
@@ -160,8 +160,6 @@ static void convert_positions(int32_t *positions, int32_t *final_positions, UCha
 
     if (score == 0.0) { for (i = 0; i < char_len; i++) final_positions[i] = -1; return; }
 
-    if (char_len == byte_len) { memcpy(final_positions, positions, sizeof(*positions) * char_len); return; }
-
     end = final_positions + char_len;
     for (i = 0; i < byte_len && final_positions < end; i++) {
         if (positions[i] == -1) continue;
diff --git a/src/calibre/utils/matcher.py b/src/calibre/utils/matcher.py
index a07aa75875..de7ed95f4b 100644
--- a/src/calibre/utils/matcher.py
+++ b/src/calibre/utils/matcher.py
@@ -217,14 +217,17 @@ def test2():
             print ('\tns', item, positions)
 
 def test():
-    items = ['m1mn34o/mno', 'xxx/XXX', 'mxnxox']
+    items = ['mx\U0001f431nxox']
     for q in (PyScorer, CScorer):
         print (q)
         m = Matcher(items, scorer=q)
         for item, positions in m('MNO').iteritems():
             print ('\tMNO', item, positions)
-        for item, positions in m('xxx').iteritems():
-            print ('\txxx', item, positions)
+            if -1 not in positions:
+                for p in positions:
+                    print (item[p], end=' ')
+                print ()
+
 
 def test_mem():
     from calibre.utils.mem import gc_histogram, diff_hists
@@ -277,4 +280,5 @@ def main(basedir=None, query=None):
 
 if __name__ == '__main__':
     # main(basedir='/t', query='ns')
+    # test()
     main()