"Has improper value for" is a predefined property to track input errors for irregular value annotations that was likely caused by type or allowed value restrictions.
en:Calculated field, based on DateYear, DateMonth, DateDay, where missing information is replaced with earliest possible value (e.g. "1999" results in 1.1.1999) +
Calculated field, based on DateYear, DateMonth, DateDay, where missing information is replaced with earliest possible value (e.g. "1999" results in 1.1.1999) +