Field label missing when reference field datatype is mediumtext

1. Navigate to Incident > Open.
2. Open an incident record.
3. Right-click on the Caller field label and select Configure Dictionary.
4. Change the Type field from Reference to String.
5. Change the Max length to 256.
6. Right-click in the header bar and select Save.
7. Change the Type field back to Reference.
8. Click Update.
9. The incident form from step two should be displayed. If it is not, navigate to the incident form.
   Note that the field label is now missing.
   
   

 Please create an incident with ServiceNow Customer Support and they will perform the data correction steps.