Populating TAG page when using the kebab filter
For your link, change {{ tag.title | kebab}} to {{ tag.slug }}

Then on your tag.html page change your tag variable to this:

{% set tag = craft.tags.slug( craft.request.segment(2) ).first() %}

This is how I have it set up and works fine.

Edit: Forgot the route needed: Add this to your routes.php: 'tags/{slug}' =&gt; 'tags/tag',