Migrating to V5 now get: Cannot use 'in' operator to search for '$ref' in false

[JonnyBhub]

Hi All,

Hopefully someone is able to help. I am currently migrating our application to v5, I've managed to sort out almost everything except one aspect that is causing me a headache now.

The error is:

Cannot use 'in' operator to search for '$ref' in false

I'm using an mui form, and where I am seeing this issue is in our custom review dialog pop up. We show the form as a read only version.
When navigating to a certain tab, the above error is happening and nothing is being rendered. I know what widget and element it's happening out but I don't know why.

My theory is that because its a custom widget that is using a hook (due to a value being calculated based on an arrayfield full of other values being added together), that it's the hook that is causing the issue. It's only happening on the tabs where the hook is being used.
Does anyone else have any experience with this issue and fixing it please?

(For security reasons I won't be able to share the code outright)

The error stacks is below:

Uncaught TypeError: Cannot use 'in' operator to search for '$ref' in false
at toPathSchemaInternal (toPathSchema.js:20:16)
at toPathSchemaInternal (toPathSchema.js:67:1)
at toPathSchemaInternal (toPathSchema.js:67:1)
at toPathSchema (toPathSchema.js:85:1)
at SchemaUtils.toPathSchema (createSchemaUtils.js:193:28)
at Form.filterErrorsBasedOnSchema (Form.js:491:1)
at Form.onChange (Form.js:126:1)
at SchemaField.js:78:1
at ObjectField.js:45:1
at SchemaField.js:78:1