Apparently, if the linked style is applied at the beginning of the paragraph it will show up in the TOC. If it is in the body of the paragraph, it will not.
I checked and while disable linked styles mattered for
using the Style, once the style is applied you can disable linked styles and the style will still appear in a TOC.
I had only tested with the style in the middle of the paragraph previously. I will have to update my page.
Character Style v Paragraph Style v Linked Style
I will keep them disabled!