Twitter Description on Twitter Card doens’t work

I am unable to recreate your issue from the post editor in WordPress 4.7.3 with plugin version 2.0.1 installed.

I entered a custom value for title and post, and title alone, for the post. The values persisted in the post editor. The markup was output as twitter:description in the post template’s meta elements.

What steps are you taking to save a custom Twitter description? Do you have the latest version of the plugin installed? Are both title and description disappearing for you?

I installed it for the first time yesterday, the version is 2.0.1 (so this is a new plugin for me).

I didn’t install the Tweet button as I already have share buttons.. I don’t know if that matters.

What I did to try it out:
I edited a previous post, scrolled down to the twitter, entered a description under the Twitter card, and clicked the update button. I did the same thing today—to double check myself, and it stayed. :/ So, I must have done something differently yesterday.

But, I think I don’t understand what the description is for. I assumed it would show on the Twitter Card, overriding the first few lines of the post the usually show up. What is it for? I can’t find it in the FAQs.

You can read about cards on Twitter’s developers site:
https://dev.twitter.com/cards/types/summary

You can read more about the plugin feature and filters in the plugin documentation:
https://dev.twitter.com/web/wordpress/cards

The Twitter plugin for WordPress outputs Twitter Cards markup for each of your posts and supports overriding a post’s title and description used to create a link preview when the post URL is shared on Twitter. When you view source of a post permalink page in WordPress and search for twitter:title, twitter:description, etc. you will see the plugin’s output of meta elements describing the post. A post excerpt is used by default; you may want to override with a more succinct description for Twitter and other social networks.

Recent example: a New York Times article and a Tweet promoting the article. The New York Times has a short description in the Twitter description, different than the first few lines of the article.

Thanks!