Last day’s I was confronted with a “invalid date” bug in an old batch-input program (BDC).
It was running well since years but from the 1st day of 2013 the called input screen popped up with this “invalid date” error.
The solution was that sy-datum was always put to a dats field in reverse order ( 20120721 ). This date was all the time misinterpreted ( as 20.12.0721 ) but since the date was not needed nobody take notice. On the 2nd of Jan. 2013, first time the error occurred because the date field was now filled with 20130102 and this leads the data validation to the misinterpretation of 02.13.0102 (European notation). Since there is no 13. month the error occurred.
Just in case anybody has the same problem 🙂