Rich Text Area Fields -> Page Error

I just created a new Rich Text field for Leads and it worked fine to my surprise. I’m creating a new case detail page to see if it’s field or page related.

PageName: Lightning_Case_ManagementPageDetail
When clicking ‘Additional Comments’ from within a Queue: Endeless spinning circle
When creating ‘New Case Comments’ (Entirely seperate custom object): Endless spining circle

PageName: Lightning_Case_Detail
When clicking ‘Additional Comments’ from within a Queue: Popup Error
When creating ‘New Case Comments’ (Entirely separate custom object): Popup Error

Popup Error /w Console:

PageName: Lightning_Lead_Detail
When clicking ‘Rich Text Area’ field: Works fine no popup error and can type & save.