Are the grants disbursed by the manager in the form of an unspecified mission cost permissible, knowing that whoever takes them feels they are illicit gain?

If an employee is not entitled to a bonus except by performing a specific task, and the manager is not authorized to grant it except to those who have performed this task, then it is not permissible for one who has not performed the task to take it, because it is an unlawful acquisition. Whoever took it must return it. If one is certain or highly presumes that the one who delivered it will not return it, then they must spend it on charitable causes and public welfare.