Why does SEPA Transfer use 01.01.1999 as the execution date?
According to the SEPA standard, the execution date 01.01.1999 for credit transfers means "earliest possible date" (formally "non-terminated credit transfer") and is always used by SEPA-Transfer if the execution date is the respective today's date.
If you specify a future date, SEPA-Transfer exports a "scheduled transfer". This contains the date as specified.
Some banks and other programmes do not accept that standard. In that case you would please have to switch to the Enterprise Edition:
In the Enterprise Edition of SEPA-Transfer, there is an option to influence this behavior in the settings under "Advanced". In the "Bank specific settings" section, check the "Execution date of non-terminated SEPA transfers is the current day instead of 01.01.1999" to always use the date you set in SEPA transfers.