No vacation consumption during agreed training period
OGH, Judgment of 29.9.2020 - 9 ObA 69/20t
During the consumption of the statutory vacation entitlement, the employee must be completely free to spend the vacation as he or she wishes. An agreement according to which part of an agreed training period is credited against the statutory vacation entitlement is invalid.
When agreeing on a granted training period, no vacation may be used up for this purpose, as this does not correspond to the meaning and purpose of vacation, namely to create a free space for self-determination. Therefore, if an employee is to be granted time for training, care must be taken not to combine this time with the use of vacation.
You can find the decision here.