Question about adding dropdown item through Hierarchical Select

I have added a dropwown item through Hierarchical Select. enter image description hereenter image description here The newly added item can be displayed properly on the client end. However, when a client selects the item and submits it, the system report an error”Plese select a campus”.error. I checked up the system log, got the following messages. Log Messages May I ask your help to fix it? Thank you!