Happy New Year ....

… Not, it is not an error, it is quite simply Ethiopian New Year's day!

“Like the calendar copte, the Ethiopian calendar has twelve 30 days months each one plus five or six epagomenes days (usually called thirteenth month), but with names into amharic. The sixth epagomene day is added every four years on August 29 in the calendar Julien, six months before the epagomene day of this last.
Thus, Ethiopian New Year's day, 1st of the month of Mäskäräm celebrates on August 30 in the Julien calendar when the sixth day is added. For the years of the Gregorian calendar going from 1901 to 2099 included, the equivalent corresponds to September 11.
To indicate the date, the Ethiopian ones used in the beginning the Era of the Incarnation, which fixes the date of the incarnation of Jesus at March 25 of year 9 of the Christian era (Julien) (chosen by Annianus of Alexandria at the beginning of Ve century). But the first calendar year began seven months earlier, on August 29 of year 8 (Julien), which involved a eight years shift with the Gregorian comput of January 1 to September 10 then a seven years shift for the remainder of the Gregorian year. “
Wikipedia.fr source