Downloading resource everytime I assemble the project

After I have added email template addon and full text search, I have noticed that the following resources are downloaded every time I assemble the project.

12:33:35.290] Executing Gradle task: assemble
Download https://jcenter.bintray.com/org/webjars/npm/codemirror/maven-metadata.xml
Download https://jcenter.bintray.com/org/webjars/npm/postcss/maven-metadata.xml
Download https://jcenter.bintray.com/org/webjars/npm/core-js/maven-metadata.xml
Download https://jcenter.bintray.com/org/webjars/npm/readable-stream/maven-metadata.xml

Any reason why?