Field name already exists

All

I have backed up a sharepoint site and restored to another environment. I have a specific list which I want to update the default value of a hidden field in powershell

I found the field, set default value. But when I call field.Update() I see the error below.

I also see this error when I try to create and index on same list. I did quite a lot of search last 2 days, but no luck.

Do you guys have any idea?

Update : Exception calling "Update" with "1" argument(s): "Field name already e xists. The name used for this field is already used by another field in the list. Sel ect another name and try again." At line:1 char:14 + $field.Update <<<< ($true) + CategoryInfo : NotSpecified: (:) [], MethodInvocationException + FullyQualifiedErrorId : DotNetMethodException