If you update a field in Autocad and the field is not updating check the following system variable to fix your issue FIELDEVAL

I add the following to my startup list for all systems.  The below also turns off the shading that indicates if a part of the text is a field.  You will still have to do a regen/regenall/plot/reopen to see the updated field data.

;; Controls how fields are updated. 31=updates in all instances
(command “FIELDEVAL” “31”)
(Command “FIELDDISPLAY” “0”)