I have created a person or group column in list. When I take list template and use it in other site the internal name of the person or group column gets changed. I have used the internal names of this column in my code. Now due to this mismatch of internal names the code is failing.
By default, the name we specify while creating the column is used as display name as well as internal name.
However we can change the display name as many times as we want, but can never change the internal name once column is created.
You have to delete old column and create new column if you want to change column internal name.