@Fran-Diox That was it! Thank you!
I was using two separate stacks, when I changed the splitter to use the same stack as the navigator it works.
<v-ons-splitter-side swipeable width="220px" collapse="" side="right" :open.sync="openSide">
<v-ons-page>
<v-ons-list>
<v-ons-list-item
v-for="menuPage in menuPages"
:key="menuPage.label"
tappable
modifier="chevron"
@click="setOptions({animation: 'fade'}); pageStack.push(menuPage.page); openSide = false"
>
{{ menuPage.label }}
</v-ons-list-item>
</v-ons-list>
</v-ons-page>
</v-ons-splitter-side>