Tab override in lightning is not 'activating' lightning navigation tab when clicked

Hello all!

I’m using a visualforce override on a standard object (e.g. Contact) and, when the tab is clicked in Lightning, it does not highlight/activate that lightning tab (see screenshot):

I’ve included here a screenshot of my override text:

and the visualforce page:

<apex:page standardController="Contact" recordSetVar="c" extensions="skuid.Redirects" action="{!redirect}?actionType=Tab&amp;objecttype=Contact">

</apex:page>

Any help much appreciated!

Hope you’re all well!

Louis