Hello,
On demo platform the "Urgency" field has "Please Select Urgency" as default value, because he has been created by an user.
This user This user added the item 'Please Select Urgency' on the list of value Urgency with a low sort order, and as he set the urgent field to oblige the list takes the first value by default.
In addition to Flou's answer, there was a change in DB to set id of this item to 0 (zero).
With this change, this value "please select a value" in not considered as a correct value and user has to select a correct value.