One observant user sent me feedback about the “remember me” or auto-login cookie expiration. He noticed that they expire relatively fast: ~24 hrs or so. I have fixed this and now the auto-login cookie should be valid for five days.
If you want to use longer auto-login, you must logout, refresh the browser properly and login.
Big thanks to user “B” 
Some users reported about error message: “DataTables warning: JSON data from server could not be parsed. This is caused by a JSON formatting error”. I managed to reproduce the error today. Some section-echoes contained non-ASCII characters which DataTables can’t handle. Characters are most likely ANSI colour codes. I modified the IRC-bot code accordingly.
Pls let me know if you see DataTables warnings about JSON formatting again and also report the page number and section in question.