"

 Menobot problem?? 

Are you running Menobot on #37, #6 and #16?  If so, it is not fixing the error and just marking it as done.  There might be a WPCleaner bug on #3 that causes this. Those weren't done by Menobot, but by another user running WPCleaner.  Hmmmm.   

Problems in 16 they maybe related to code update recently.    

 Thank you both for your comments. I am stopping the bot from doing this task and I am reporting this issue.   
Should be fixed for #16 with the update I made a few hours ago. If there are problems with other errors, tell me.  (Talk on frwiki) 
    Still doesn't explain why #6 and #37 were being marked as done, but not fixed.    
, could you give me examples of articles that were marked as done but not fixed for #6 and #37 ? I took a look at a few #37 that have been marked as done, and either they were really fixed by WPCleaner (like Fröken Fräken or Günther's frog (disambiguation)), were fixed by someone else (like Adolfo Fernández) or I don't understand why they were detected for #37 (like 1971–72 New York Nets season or Emergency Afghan Allies Extension Act of 2014 (H.R. 5195; 113th Congress)).  (Talk on frwiki) 
  For #37: Chris & Matt Kidd, 2014 Västmanland wildfire, Korea — Anti-Dumping Duties on Imports of Certain Paper from Indonesia and Blum & Poe
For #6: Gå & fiska!   

For #37, did you change the way it's handled by Check Wiki? As far as I can remember, #37 was only checking the first few characters of the title (it was 3 for a long time, and then was changed to 5 sometime ago). For all the examples you provided, the special character is after the fifth character, so it shouldn't have been picked up by #37.
For #6, the DEFAULTSORT that has been added by WPCleaner is ""Ga & fiska!"", which for me is ok. Which character is considered a special one by CW ? ""&"", ""!"" ?
 (Talk on frwiki) 
 For #37: Yes. Now we check the entire string. We should also warn .    
 For #6: I rename ""&"" to ""and"" and remove ""!"".    
 Could you give me the list of characters that CW considers as normal characters? For WPCleaner, I'm currently using the following list: ASCII letters, digits, space and a few punctuation -:,.!?'