Unable to assign Add Project Proposal form if Cover Image is on the form

Heads-up on this one if you are struggling to assign Add Project Proposal form if Cover Image is on the form as it was a tricky one to figure out what field component was causing it.

When the form has a "Cover Image" placed on the form, the form is not able to be assigned in Summary & Settings > Project > Forms

When the "Cover Image" is removed from the form, the form is now able to be assigned in Summary & Settings > Project > Forms.

SR raised and will update with any progress.