Ion-back-button not rendering

I am currently using the vue version of the ionic framework.
I implemented the back button as it lists in the docs, but the button will not render in the HTML source code. The router and routing are set up properly, so there is history to use.

The default-href attribute didn’t change anything either.

Secondary Page:

    <!-- Back Button -->
    <ion-buttons slot="start">

Previous Page:

<ion-item :router-link="`/details/${item.dealID}`">