diff -r 98e2835b787a roundup/anypy/email_.py
--- a/roundup/anypy/email_.py	Tue Sep 29 17:12:20 2020 -0400
+++ b/roundup/anypy/email_.py	Thu Oct 08 16:48:24 2020 +0200
@@ -108,8 +108,8 @@
     collapsed = []
     last_word = last_charset = None
     for word, charset in decoded_words:
-        if isinstance(word, str):
-            pass
+        if isinstance(word, str) and bytes != str:
+            word = bytes(word, 'raw-unicode-escape')
         if last_word is None:
             last_word = word
             last_charset = charset