This is normal, to do the translation
is in lang_extra.txt

days

                         |Fri |Fri |
                       [color=red]   |Mon|Mon|
                         |Mon |Mon [/color]|
                         |Sat |Sat |
                         |Sun |Sun |
                        |Thur |Thur |
                         |Tue |Tue |
                         |Wed |Wed |