I'm unable to replicate this, it looks like it works: https://en.wikipedia.org/api/rest_v1/data/citation/mediawiki/10.1098%2Frsta.2014.0376
I'm also able to add this doi on en wiki.
Are you still having this problem? What language wiki are you on? If you're still having a problem with it it may be an issue with your local wiki's configuration.