Error When Creating a New Page Document Type

Hi all, new here and fairly new to Sanity so apologies if this isn't the best place to put this, but I've started getting this error when I go to create a new page. It doesn't happen for any of my other document types, only for pages. Does anyone know what might have caused this? I've tried rolling back but it didn't fix the issue.

Hi Geoff, thanks, I just removed an initial value from a string field and that seems to have fixed it. I removed the portion in bold.
name: 'template',
type: 'string',
title: 'Template',

initialValue: {
title: 'Default',
value: 'default',
}, options: {
list: [
{ title: 'Index', value: 'index'},
{ title: 'Contact', value: 'contact'},
{ title: 'Simple', value: 'simple'},
{ title: 'Default', value: 'default'}
],
},

Glad to hear it! If you want to retain the initialValue for a string list, you can add it back like this:

It can be a bit confusing because when setting initialValue on the document, you
do it as an object , but when setting it on the string field, it’s done as a string (or a function).

Glad to hear it! If you want to retain the initialValue for a string list, you can add it back like this:

It can be a bit confusing because when setting initialValue on the document, you
do it as an object , but when setting it on the string field, it’s done as a string (or a function).

Thanks!