When having workflow enabled, if a translation is added and the document is pending, it will automatically increase the article version. This is because only draft is being checked, if it is draft the version will remain the same. More validations should be added.
The method is JournalArticleLocalServiceImpl.updateArticleTranslation

"if (!oldArticle.isDraft())" should be replaced by "if (!oldArticle.isDraft() && !oldArticle.isPending())"

To reproduce start Liferay with Kaleo Workflow.
Upload translation-fork-definition.xml. Apply translation workflow to Web Contents.
Add admin user to workflow roles
Create a web content, submit, accept workflow task, submit task for translation, accept spanish translation task, edit the web content, click "add a translation", type something and save the translation. While still in the Web Content editor you should see the version increased to 1.1 (and the document was still in pending state)