The only updates were to Jetpack. I’ve disabled jetpack and there was no change in behaviour on the settings page or the plugin’s inability to convert tagged posts.
I’ve turned on debug in the wp-config.php file and enabled logging. There are no errors logged.
I did notice when looking a the page source that all of the html elements have the text commented out.
i.e. Here’s the anchor tag for the first tab.
<a href="#gp-overview" class="ui-tabs-anchor" role="presentation" tabindex="-1" id="ui-id-1"><!--? _e('Overview','tpg-get-posts')?--></a>
Is that normal?
Thanks for your help!