Unable to add specific metadata field/value to item

[LEavestaff]

Describe the bug We are unable to add the metafield 'dc.description' to an item in the edit item page in the UI. The field does not appear in the dropdown, and it gives the error message 'Please choose a valid metadata field'. This is despite us having the metadata field registered, and we have tried removing adding back the field in the registry but the issue still remains. It seems to be only this field that has the issue.

We have a customised instance of DSpace 7.5 installed currently. We first noticed this issue before production release last year but are unable to diagnose the issue.

To Reproduce

1. Login as an admin
2. Find an item and then edit the item
3. Add new field in the edit item view and type 'dc.description'

Expected behavior Field 'dc.description' is accepted as a valid metadata field to be added

Related work N/A