Hi,
We will break this down by search engine
A. Duck Duck Go and Bing
Duck Duck Go pulls from other search engines to show its results, such as from Bing. If the URL is appearing correct on Bing it is likely to also appear correct on Duck Duck Go.
We looked at an example URL like https://healthyhappywoman.co.uk/happiness/resistance-is-futile/ and can confirm Yoast is outputting the meta description correctly. See image: https://pasteboard.co/JgqpeH2.png
However, we can see in Bing here it is not showing that.
If you clear all your caching and then use Fetch as Bingbot: https://www.bing.com/webmaster/help/fetch-as-bingbot-fe18fa0d does the issue resolve? This will force Bing (and eventually Duck Duck Go) to update the index and hopefully show the right meta.
B. Google
We can see Google is showing the right meta description here.
If Google is showing different meta descriptions when you search, to resolve the issue we suggest three actions:
1. We ask that you improve the meta description.?Google sometimes changes the meta description to be more descriptive and to help users when they search.?This guide explains more: https://yoast.com/help/my-meta-descriptions-arent-showing-up-in-the-search-result-pages/. You can learn more about improving them with this guide: https://yoast.com/meta-descriptions/.
2. Then use?Inspect Any URL to encourage Google to reindex the page and update the search results accordingly. Check in Google to see if the right one then appears. This guide explains more about that tool: https://yoast.com/help/fetch-as-googlebot/.
3. Consider contacting Google by making a post on their forum and asking them why Googlebot is changing the meta description. You may contact Google here: https://productforums.google.com/forum/#!forum/webmasters.